For centuries, buildings have been remarkably simple.

Heat escaped through draughts, moisture dried naturally through ventilation, and indoor temperatures closely followed the weather outside. Buildings were often uncomfortable and inefficient, but they were also surprisingly tolerant of things not being perfect.

Over the last few decades, that has changed dramatically.

To reduce carbon emissions and energy consumption, modern buildings have become increasingly airtight and insulated. These improvements have delivered enormous benefits, but they have also shifted much of the responsibility for comfort and efficiency away from the building fabric and onto the systems serving it.

The challenge today is no longer simply building a better building.

It is ensuring that increasingly complex systems are properly designed, commissioned, reliable and simple for occupants to operate.

The question has become:

• What systems does a building rely on?
• What happens when they aren’t working as intended?

Heating Systems: Small Changes, Big Impacts

In older buildings, heating systems are often pretty crude.

A boiler supplied water to radiators at high temperatures and occupants adjusted comfort by opening windows, turning thermostats up and down or simply just off and on.

Modern heating systems are far more sophisticated.

Heat pumps, weather compensation controls, zoning systems, underfloor heating and smart controls can significantly reduce energy consumption while maintaining comfort. However, these systems only achieve their promised performance when configured correctly.

A heat pump operating at unnecessarily high temperatures can dramatically increase electricity use. Poorly configured controls can lead to overheating, excessive cycling or rooms failing to reach their target temperatures.

Increasingly, the issue is not that a building lacks heating capacity. It is that the system requires careful setup and optimisation to ensure the heat efficiently gets in a building and then is effectively distributed around it.

Cooling Systems: A Growing Necessity

Historically, many UK buildings required little or no cooling.

The climate was generally mild enough that opening windows during warm weather was sufficient.

As summers become warmer and periods of extreme heat become more frequent, cooling is becoming increasingly important. Building fabric issues that just mean a slightly bigger bill in the winter months can mean huge discomfort for occupants in the summer months.

Most buildings in England are dependent of overnight window or door opening to cool them down with cooler overnight air. As the days and nights have got warmer buildings have become hugely dependent on this overnight ventilation that is dependent on occupant action or simply may not be possible or practical.

Cooling can come in many forms:

• Mechanical night purge ventilation systems
• External shading controls
• Air conditioning
• Reversible Air-to-Water heat pumps

The challenge is that cooling systems often interact closely with the building itself.

A poorly shaded building may require far larger cooling systems than originally expected. Similarly, cooling systems may perform poorly if controls are incorrect or ventilation strategies are not coordinated.

Good cooling design is increasingly becoming a necessity rather than a luxury.

Ventilation and Indoor Air Quality

Perhaps the clearest example of growing system dependence is ventilation.

Traditional buildings leaked air continuously through gaps and cracks. Even traditional buildings these days often have had a lots of their draughts minimised over time.

Modern buildings are intentionally sealed to minimise heat loss. While this dramatically improves energy efficiency, it also means fresh air can no longer be left to chance.

Instead, buildings increasingly rely on systems:

• Manual window and door opening
• Mechanical extract ventilation
• Positive input ventilation systems
• Mechanical Ventilation with Heat Recovery (MVHR)
• Air quality controlled ventilation (in high end environments)

When these systems are working correctly, indoor environments can be healthier, quieter and more energy efficient than ever before.

When they are not, occupants may experience:

• Poor air quality
• Excess humidity
• Condensation
• Mould growth
• Overheating
• Increased energy use

Ventilation systems often require regular maintenance, filter replacement and commissioning checks to continue performing as intended.

Domestic Hot Water Systems

Hot water is another area where modern buildings have become increasingly reliant on controls.

To improve efficiency, many systems now include:

• Heat pumps
• Solar thermal systems
• Thermal stores
• Smart immersion controls
• Time scheduling
• Legionella protection cycles

These systems can reduce energy use significantly but often require careful setup.

Poorly configured timers, excessive water temperatures or incorrect control settings can increase running costs without improving comfort. They do represent an opportunity as hot water cylinders can often be reheated at off-peak times, making use of reduced energy prices.

Renewable Energy Systems

Many buildings now generate a proportion of their own energy or make use of the outside environment. This flips the conventional model on its head as there is much more energy outside than there is inside and how can that be harnessed to make huge gains in building performance.

Examples include:

• Heat Pumps
• Solar PV
• Battery storage
• Smart EV charging
• Export controls
• Energy management systems

These technologies can deliver substantial savings, but only when they operate together effectively.

It is increasingly common to find buildings where expensive renewable technologies have been installed but are not performing as expected because settings have never been reviewed following installation.

Sensors, Controls and Automation

Modern buildings are increasingly becoming data-driven.

Temperature sensors, occupancy sensors, CO₂ monitors and smart controls continuously influence how systems operate.

In many cases, the controls have become just as important as the equipment itself.

The reality is that a perfectly sized heating or ventilation system can still perform poorly if sensors are located incorrectly or control strategies are misunderstood.

Often, energy waste occurs because systems are simply fighting each other:

• Heating and cooling operating simultaneously
• Ventilation rates set too high
• Hot water unnecessarily maintained at peak temperatures or not heated at off peak times
• Controls overridden and never reset

Commissioning: The Often Forgotten Stage

The unfortunate reality is that many systems are installed correctly but never fully commissioned. This agonisingly may mean they never reach their full potential but it may only be one simple setting change away.

Commissioning is the process of ensuring every component operates as intended and that the whole building works together as a single system.

Without commissioning:

• Energy use can be significantly higher than expected.
• Comfort problems can persist.
• Equipment lifespan may be reduced.
• Occupants often lose confidence in the building.

A building’s long-term performance frequently depends more on commissioning and ongoing optimisation than on the equipment itself.

A New Era of Building Performance

The buildings of the future are unlikely to become simpler.

In fact, they will probably become even more dependent on carefully integrated systems. However, there is progress being made to make controlling these systems simpler to the occupant or setup so they just work and never have to be changed.

Heat pumps, ventilation systems, renewable energy technologies, smart controls and cooling systems all have important roles to play in helping buildings respond to rising energy costs and a changing climate.

The opportunity is enormous.

When these systems are operating properly, buildings can be healthier, more comfortable and far cheaper to run than previous generations ever achieved.

The challenge is making sure those systems are actually doing what they were designed to do.

How Woohoo Can Help

We help clients understand how their buildings are really performing.

Modern buildings rely heavily on systems such as heat pumps, ventilation, cooling and controls to deliver comfort, good air quality and low running costs. Even well-designed buildings can underperform if these systems are not properly commissioned, configured or maintained.

We work with clients to assess:

• Heating and cooling performance
• Ventilation and indoor air quality
• Energy consumption and running costs
• Overheating and occupant comfort
• Renewable energy systems

By combining building physics with real-world operational data, we help identify where energy is being wasted, where comfort issues are occurring and what practical improvements will deliver the greatest benefit.

As buildings become smarter and more dependent on technology, understanding how those systems work together is becoming just as important as the building itself.

The goal is simple: comfortable, healthy buildings that perform as intended while keeping energy use and running costs under control.

During a heatwave, many people assume that hot air outside is the main reason their building becomes uncomfortable. In reality, most overheating problems are caused by a combination of heat gains from several different sources, all adding heat faster than the building can remove it.

The challenge is that buildings behave a bit like a thermal battery. Throughout the day they absorb heat from the sun, occupants, lighting and appliances. If this heat cannot escape overnight, the building starts the next day already warm and temperatures continue to climb.

Understanding overheating therefore comes down to two simple questions:

1.         Where does the heat come from?

2.         Why can’t it get out?

Part 1: Heating – Where Does the Heat Come From?

Solar Gain: The Biggest Contributor (50-70%)

In most homes, solar gain through glazing is by far the largest source of overheating during a heatwave. Sunlight enters through windows and is absorbed by walls, floors and furniture. These surfaces then re-radiate heat into the room, creating the familiar greenhouse effect.

A typical south or west-facing window can admit hundreds of watts of heat during sunny periods. In many modern well-insulated buildings, solar gain can account for well over half of the total heat entering the building on a hot day. This is why external shading often provides more overheating benefit than additional insulation.

Building Fabric (10-20%)

Roofs, walls and windows also absorb heat directly from the outside environment. Dark roofs can reach temperatures of 60-80°C on sunny days, transferring some of this heat into the occupied spaces below. Poorly insulated lofts and roof spaces are particularly prone to this effect.

However, contrary to popular belief, heat transfer through walls is often a smaller contributor than direct sunlight through glazing. Often it’s uninsulated roofs that provide large heat gains in the building fabric

Occupants (5-10%)

People are effectively small heaters.

An adult sitting quietly typically emits around 70-100 watts of heat. A family occupying a house may contribute the equivalent of several hundred watts continuously, particularly during evenings when windows are often closed for security or noise reasons.

Appliances and Lighting (10-20%)

Every unit of electricity used inside a building eventually becomes heat. Computers, televisions, cooking appliances, hot water systems and lighting all contribute. A gaming PC can release several hundred watts. An oven can release several kilowatts while cooking. Even efficient LED lighting ultimately converts its energy into heat within the room.

These gains are often overlooked because they are less obvious than sunshine through a window.

Ventilation and Hot Outdoor Air (5-15%)

Opening windows during the hottest part of the day can make overheating worse.

If outside air is warmer than the internal air temperature, ventilation becomes a source of heat gain rather than cooling. Buildings therefore need carefully timed ventilation rather than simply opening every window whenever it feels warm even if the strong breeze makes things feel much more comfortable.

Part 2: Cooling – How Does the Heat Escape?

Getting heat out of a building relies on surprisingly few mechanisms.

Ventilation

The most effective cooling method available to most buildings is moving cooler outside air through the building. When night-time temperatures fall, opening windows or using mechanical ventilation allows stored heat to be carried away by the cooler air.

The greater the airflow, the faster cooling occurs. It’s this overnight airflow that has the greater impact in cooling buildings. Ideally looking to be capable of 5+ air changes per hour which is a large continuous draught.

Unfortunately, during still nights there may be very little natural air movement, so simply opening windows does not always provide the cooling people expect as the temperature or humidity difference alone is not enough for the air to flow at a significant speed.

Night Purge Cooling

The goal of night ventilation is not primarily to cool the air.

Instead, it cools the building fabric itself. Walls, floors and ceilings often store far more heat than the air in the room. If these surfaces can be cooled overnight, they effectively reset the building ready for the next day.

This explains why a house can still feel hot at midnight even after outside temperatures have fallen. The goal of night purge cooling is to flush the building with as much cooler air as possible. Often this requires fans near windows to help draw the air through the building.

Radiation to the Night Sky

Buildings also lose heat through radiation. Roofs, walls and external surfaces continuously emit heat to their surroundings. On clear nights they can become surprisingly effective at shedding heat directly to the sky.

While invisible to occupants, this process contributes to overnight cooling and is particularly important for lightweight roofs.

Thermal Mass

Thermal mass often receives mixed publicity because it can both help and hinder overheating.

Heavy materials such as concrete, stone and brick absorb heat during the day and slow temperature rises. However, if the building cannot cool at night, that stored heat remains in the structure and may contribute to overheating for several days.

Thermal mass can therefore be really helpful as it can slow the building heating up but needs a lot of cooling air flow to draw the heat out of the building fabric.

Active Cooling

When natural ventilation and shading are insufficient, active cooling may be required. With more frequent heat waves we are getting more nights where the outdoor temperature doesn’t drop below 20 degrees C and thus air needs to be moved much faster through the building overnight to cool it.

Air conditioning removes heat directly from the building and rejects it outdoors. While highly effective, it should generally be considered after first reducing solar gains and improving ventilation opportunities to reduce the amount of cooling required.

A number of people with heat pumps and underfloor heating are switching their heat pumps into cooling mode which can give a very significant cooling effect by removing heat from the floor slab. Whilst effective, care should be taken with this as cold surfaces can create condensation and lead to building issues.

A surprising amount of overheating can often be solved without installing significant cooling equipment.

How Woohoo Can Help

At Woohoo, we help clients understand exactly why their building overheats as part of their wider energy and sustainability strategies. Every building behaves differently, and measures that work well in one property can sometimes have little effect in another.

By assessing heat gains, ventilation pathways and building fabric performance, we can identify where the heat is coming from, where it is getting trapped, and which improvements will provide the greatest benefit.

The goal is simple: how can we make buildings more comfortable during increasingly frequent heatwaves while avoiding unnecessary energy use and cost.

Simon Lock, our Sustainability Director, recently completed Carbon Literacy training with Futureproof Cumbria. Here are some of his thoughts on making cleaner, cheaper energy choices easier to understand.

Did you know that when it’s windy and sunny, electricity can be both cheaper and lower carbon?

It’s a simple idea, but it rarely feels simple in practice.

For owners of older buildings, heritage assets and public estates, energy decisions are rarely straightforward. These buildings often come with higher running costs, fabric constraints, planning considerations and long-term responsibilities. Not every improvement can be made quickly, and not every building can be treated in the same way.

But some decisions can still be simpler than we make them.

What if everyday weather forecasts also told us when energy was cheapest and cleanest? Suddenly, small choices such as doing the laundry, charging an EV, running appliances or planning higher-energy tasks can become useful financial and climate actions.

The Carbon Literacy Project

As Sustainability Director at Woohoo, I spend a lot of my time helping reduce emissions across the built environment, particularly where buildings are older, listed, sensitive or difficult to change.

As part of my CPD last year, I undertook Carbon Literacy training with Futureproof Cumbria. While I already had a good knowledge of emissions, there are always opportunities to improve, question assumptions and look at where small actions can lead to wider change.

As part of the certification process with The Carbon Literacy Project, you make pledges on a personal and community level to find ways to collectively reduce emissions.

Like many people working in this space, I have already made significant personal changes, including switching away from fossil fuels and continuing to lower my own emissions where I can.

So the question became: what next?

From personal action to wider impact

One takeaway stood out: the importance of sharing knowledge with as many people as possible.

Not in theory, but in practice.

At the moment, the UK is still turning off large amounts of renewable energy, during an energy crisis.

When wind generation is high, turbines can be switched off because the grid cannot absorb the excess electricity. At the same time, we may end up using more expensive gas-generated electricity later, when demand rises and renewable generation is lower.

In 2026 so far, we have collectively spent over £800m turning off wind turbines, according to wastedwind.energy.

This is a huge missed opportunity. Not just for the energy system, but for households, businesses, building owners and local authorities who are all trying to manage bills and reduce emissions.

In many cases, the action itself is not complicated. It could be as simple as shifting daily tasks away from the late afternoon and early evening peak, or planning larger weekly tasks for times when renewable energy is more plentiful.

For heritage building owners, this does not replace the need for proper fabric-first advice, sensitive retrofit or long-term decarbonisation planning. But it can sit alongside those measures.

It is a low-disruption way to understand energy better, use it more intelligently and make existing buildings work harder before larger interventions are made.

The data already exists. Forecasts for wind and solar generation are produced continuously by the Met Office and the National Energy System Operator. But they are not always presented in a way that helps people act.

If you want to see this in practice, this website gives a useful view of forecasted emissions and prices: Click here

So why not make this forecast highly visible, as part of everyday life?

Making energy patterns visible

Imagine this as part of a standard weather forecast:

• “High winds overnight — a good time to charge your EV.”
• “Strong sunshine today — useful time to run appliances.”
• “Still and overcast — energy likely to be more expensive and carbon intensive.”

Small signals. Scaled across millions of people.

For those on time-of-use tariffs, this kind of visibility could unlock real savings. In some cases, even allow people to earn money by using electricity when supply is high.

For everyone else, it builds awareness. And awareness drives change.

Only around 10% of buildings are on time-of-use tariffs and the vast majority of people could save money on these tariffs if they can make small adjustments to their usage patterns. If people moved to time-of-use tariffs they would respond to price cues that would be chasing renewable energy and get financially rewarded for doing so.

It will not solve every challenge. Heritage buildings still need the right advice, the right interventions and a proper understanding of their fabric, use and significance.

But better energy visibility can help people make better choices now, while those longer-term plans are developed.

Beyond cost: unlocking system-wide benefits

The impact goes further than individual bills. Better alignment between demand and renewable supply could:

• Reduce wasted clean energy
• Lower system costs
• Encourage greater investment in renewables
• Support grid stability
• Help organisations reduce operational emissions
• Support progress towards Net Zero

Importantly, it also makes low-carbon living more accessible.

Not something reserved for specialists. Not something only available through major capital projects. But something embedded into everyday decision-making.

For heritage and older buildings, that point is important. Decarbonisation is not always about doing the biggest thing first. Sometimes it starts with understanding the building, understanding the energy system, and making better choices with the information already available.

From insight to action

The Carbon Literacy Project has highlighted this campaign in their latest blog to try to help generate a ripple effect. Turning individual understanding into simple collective and effective action.

For me, that meant taking a simple idea and pushing it further: advocating for clearer, more accessible energy information and exploring how communication, not just technology, can unlock change.

Because the transition to a low-carbon future is not only about infrastructure.

It is about behaviour. It is about visibility. And ultimately, it is about people.

A simple takeaway

If it is sunny and windy, electricity is often cheaper and greener.

In the first two parts of the Hot Topic series, we explored running costs and energy consumption for common UK heating systems. This final section looks at the greenhouse gas emissions involved, using the same 100m² example home.

Emissions are shown as CO²E using the government’s latest conversion factors, which take into account all major greenhouse gases. Electricity figures reflect the current national grid mix, which still includes a large share of gas generation.

Hydrogen Boiler

Pros: No emissions from your building, potential for the future
Cons: Currently costly to run and wastes energy in production

Hydrogen itself burns cleanly but producing it requires a huge amount of electricity. Green hydrogen, made entirely from renewables, has very low emissions, while hydrogen created using grid electricity has very high emissions. Its impact depends entirely on how it is produced.

Oil Boiler

Pros: A practical and widely used choice for properties that aren’t connected to the gas grid.

Cons: Produces some of the highest emissions of any commonly used heating fuel due to the nature of kerosene.

Kerosene is a fossil fuel and has the highest emissions of the fuels compared in this series.

Liquid Petroleum Gas (LPG) Boiler

Pros: A workable heating solution for off-grid homes where other fuels aren’t suitable.

Cons: LPG remains an expensive and carbon-intensive fuel despite its convenience.

LPG is another fossil fuel option, and using it for heating has a large amount of emissions associated with it.

Gas Boiler

Pros: A reliable, accessible and generally affordable heating method with lower emissions than other fossil fuel options.

Cons: Still dependent on a fossil fuel, so it contributes directly to carbon emissions.

Gas boilers are common in part because gas produces fewer emissions than oil or LPG leading to improved air quality.

Electric Storage Heaters

Pros: Straightforward to install and well-suited to smaller, well-insulated spaces where heat demand is modest.

Cons: Running costs climb quickly in larger or draughty homes, especially when powered by grid electricity that still includes a significant gas contribution.

Electric heating only becomes low-emission when powered by clean electricity. As much of the UK grid still relies on gas, emissions for storage heaters currently sit close to gas heating. A renewable tariff helps push the grid in the right direction towards net zero.

Electric Infrared Heaters

Pros: Inexpensive to install and effective for heating specific areas rather than whole rooms, helping keep energy use down when managed properly.

Cons: Poor use can lead to cold spots, condensation and damp issues, particularly in buildings heated intermittently.

Infrared heaters operate at almost 100% efficiency and use less energy because they are easy to target. Problems arise when buildings are under-heated, leading to cold spots, condensation and mould, especially when users switch them on only when inside the building.  

Air Source Heat Pumps

Pros: Capable of delivering lower running costs than gas when well-installed, with government grants available to support the upfront investment.

Cons: Installation is costly and performance can dip in very cold conditions, so not every home will achieve the same level of efficiency.

Heat pumps create far more heat than the electricity they consume, so their emissions are much lower than boilers or resistance heating. This efficiency is a major reason behind the government’s net-zero strategy.

Ground Source Heat Pumps

Pros: Extremely efficient with low energy consumption thanks to the stable temperatures beneath the ground.

Cons: Installation can be expensive and complex, often requiring extensive groundwork that limits where they can be used.

Ground source systems use even less electricity than air source models, resulting in lower emissions. However, cost and installation requirements limit where they are suitable.

Log Burner

Pros: Can be relatively inexpensive to fuel and works well in off-grid settings.

Cons: Delivers heat to a limited area and is less efficient than modern whole-house heating systems.

In theory, emissions can be lower than heat pumps at present because sustainably sourced wood can have its carbon reabsorbed over time. However, log burners are inefficient, heat only small spaces and rely on forestry that cannot scale nationwide.

Biomass Boiler

Pros: A renewable heating option with running costs that compare favourably to fossil fuel systems.

Cons: Requires dedicated storage space and regular fuel deliveries and isn’t suitable everywhere due to fuel supply and sustainability considerations.

Biomass boilers currently have the lowest operational emissions because their carbon cycle is relatively short. They still produce other greenhouse gases, require significant fuel storage and depend on sustainable forestry that cannot meet UK-wide demand. They are effective where waste wood is plentiful, but not a scalable national solution.

Summary

The direction of government policy becomes clear when you consider emissions. Electricity offers the best pathway to net zero because it can be fully decarbonised. Heat pumps reduce overall energy demand and generate far fewer emissions, making them the strongest large-scale option available today. Other technologies will still have their place, but heat pumps remain the most practical route for households aiming to cut their carbon footprint.

As the UK’s storm season sets in, homes and commercial buildings across the country are tested, but older and heritage buildings often feel it more. From draughty windows to leaking roofs, traditional materials and designs mean these properties can need extra care when the weather turns cold, wet, and windy.

This blog explores small but effective ways to protect your heritage building, save money, prevent damage, and stay comfortable through the winter.

1. Keep the rain out: gutters, downpipes and roofs

Blocked gutters and cracked downpipes can quickly lead to leaks and water damage, particularly during prolonged periods of rain. Regularly clearing debris and checking for blockages keeps water moving away from the walls and foundations rather than soaking into them. It’s also worth remembering that drier building fabrics are far cheaper to heat; it takes a surprising amount of energy to warm up moisture held within walls, floors and roofs, so keeping water out directly supports lower heating bills.

Likewise, inspecting the roof for loose slates or tiles can help prevent moisture finding its way inside and causing costly internal damage during storms.

2. Cut the draughts, not the character

Heritage homes often lose heat through ill-fitting doors and windows. Weatherstripping and discreet draught-proofing can make a noticeable difference without altering the building’s appearance. Reducing air leaks not only keeps interiors warmer but also helps lower energy bills during extended cold spells.

3. Prepare your heating system

Before the worst weather hits, bleeding radiators ensures they’re running efficiently and delivering consistent warmth. In older buildings where heat loss can be high, every bit of efficiency counts it’s a simple, quick job that can make your system more effective when you need it most.

4. Make use of windy weather

High winds aren’t all bad news they can mean lower-cost, low-emission electricity on dynamic tariffs. If your home uses modern energy solutions, such as smart meters or variable tariffs, keeping an eye on when wind energy peaks could save you money while reducing carbon impact.

5. Manage airflow and prevent unnecessary heat loss

Ventilation is vital for heritage buildings, but too much can make interiors uncomfortably cold. Adjusting or temporarily closing a proportion of vents in extreme weather can strike a balance between preventing damp and retaining warmth. Windbreaks, such as hedges or fencing, can also reduce direct wind exposure and the rate of heat loss from external walls.

Caring for a heritage property through winter doesn’t need to be complicated. Regular checks, simple maintenance, and a few smart adjustments can go a long way toward keeping your building warm, dry, and efficient, without compromising its character. If you’re unsure where to start, our expert team can help you assess your building’s condition and find the most effective, sympathetic improvements for your home.

If you own a heritage building or home, talk to us about improving its comfort and performance this winter. Get in touch with us today.

Feeling powerless against rising energy bills? The latest price cap announcement allows suppliers to increase their prices by up to 4% per unit, meaning households will pay more for gas and electricity. While the price cap was originally designed to protect households from extreme price hikes, it must also be set at a level that prevents energy suppliers from going out of business. This means switching providers is no longer a reliable escape, and that the smarter long-term solution lies in home improvements that permanently cut energy usage.

While there are potentially small savings to be had by switching to a fixed-rate contract, the greatest gains come from reducing your energy consumption, as that directly lowers costs no matter which tariff you’re on.

Opportunities with Electricity

Switching to electricity opens new avenues unavailable with gas or oil. By using time-of-use tariffs, you can schedule energy-hungry tasks for when electricity is cheapest. Overnight rates are often a fraction of daytime prices, letting you run appliances, charge an electric vehicle, or heat water for much less. This simple shift offers more control than any flat-rate fossil fuel tariff.

A Step Further?

Agile tariffs change prices every half-hour, reflecting the wholesale market. This encourages you to shift consumption to cheaper periods, for example, midday in summer when solar power is abundant, or overnight in winter during windy conditions. Programming appliances to run at these times can significantly cut costs. An agile tariff rewards you for using power when the grid is cleanest and cheapest.

Reducing Consumption

The most immediate savings come from lowering demand. Focus on your building’s fabric and systems first:

• Upgrade Insulation: Insulating walls, floors, and lofts is the most effective way to prevent heat loss. Using sustainable materials such as wood fibre or recycled cellulose improves performance while reducing environmental impact.
• Control Airflow and Recover Heat: A Mechanical Ventilation with Heat Recovery (MVHR) system provides fresh, filtered air while recovering up to 90% of heat from outgoing stale air.
• Choose Smart Lighting and Appliances: LEDs and A-rated appliances drastically cut electricity use without changing habits.
• Install Renewable Heating: Replacing a gas or oil boiler with a heat pump can provide up to four times the heat for each unit of electricity used.

Generation

Generating your own power at home is a major step towards energy independence, with both solar panels and wind turbines offering distinct pros and cons. Solar panels are practical for most homes, providing clean daytime electricity, though they only convert 20–30% of sunlight and don’t work at night without batteries.

Wind turbines are more efficient and operate 24/7 in the right conditions, but require high upfront costs, space, and can be visually or audibly disruptive, best suited to rural or exposed areas.

Batteries help balance generation, though some energy is lost in charging and discharging.

How We Can Help

Every building is different. We can be your trusted guide, helping you choose the most impactful and cost-effective improvements for your heritage property, whether insulation, heating, or renewables, so that all upgrades work together to create a more efficient, comfortable, and future-proof home.

Our goal is to help buildings use less energy. Insulation can halve heating demand, and a heat pump uses a quarter of the energy of a gas boiler. With lower demand, bills fall, and less on-site generation is needed. Flexible electricity use can unlock further savings.

If you own a heritage building or home and want tailored advice on reducing energy use without compromising its character, get in touch with us today.

In the first part of this series, we examined the running costs of various heating systems.

In Part 2, we now remove the fuel cost and analyse how much energy they use, as well as their efficiency.

As with part 1, we are comparing common UK heating options using a standard 100m² home with typical heat loss. Each situation will vary, but this example illustrates the trends in the amount of energy different heating systems consume.

Log Burner
Traditional, potentially cheap but inefficient.

• Pros: Relatively inexpensive fuel, works off-grid
• Cons: Inefficient and localised heat typically to the room it’s in.

Log burners are a common sight throughout the UK, and many people have access to cheap or even free logs. The downside is that they are one of the least efficient methods of heating a home from burning a fuel. They can heat up a room quickly as they are very powerful, using radiant heat to make the space feel warm. However, compared to a biomass boiler, less of the energy in the wood is converted into useful heat for your room.

Oil Boiler
Common off-grid option.

• Pros: Good efficiency, widely available off-grid
• Cons: Price is still volatile, carbon emissions

Now we are moving into the boilers that burn things in a contained environment to heat water for a central heating system. Newer condensing type boilers are more efficient, extracting upwards of 90% of the energy available in the kerosene. Older boilers are usually non-condensing, which are less efficient. All of the following modern boiler types have very similar efficiencies.

Biomass Boiler
Renewable option with reasonable running costs

• Pros: Renewable, lower running cost
• Cons: Needs storage space, frequent deliveries

Biomass boilers commonly use wood chips or similar for fuel. Much more efficient than a log burner and has similar efficiency to other boilers. The disadvantage of biomass boilers is that the fuel is less energy-dense, and thus, it commonly requires more frequent deliveries of fuel.

LPG Boiler Central Heating System
Off-grid solution, but pricey fuel

• Pros: Suitable for off-grid homes
• Cons: Expensive fuel

Liquefied Petroleum Gas (LPG) boilers are typically the most expensive to run of the boilers due to the fuel price, but have a similar burning efficiency to other boilers. Commonly used in more remote locations as it can be stored in tanks.

Gas Boiler
The UK standard for good reason

• Pros: Affordable, reliable, widely available
• Cons: Still a fossil fuel

The most common boiler fuel in the UK is natural gas. These are now achieving around 95% efficiency and burn very cleanly, which has helped reduce pollution in urban environments.

Hydrogen Boiler Central Heating System
Future-friendly but still similar efficiency to other boilers

• Pros: No emissions from your building, potential for the future
• Cons: Is still burning a fuel to create heat with high current hydrogen prices

Hydrogen is likely to have a role to play in our net zero journey but projections are suggesting it is not going to be the boiler of choice for most future homes. It may become a more off grid solution or an option in places where electricity generation, storage and supply have challenges.

Electric Storage Heaters
Simple but costly for larger spaces

• Pros: Easy to install and efficient, good for small, well-insulated spaces
• Cons: Expensive to run in bigger or draughtier homes

We now move into the heating systems powered by electricity. Electric heating is often considered to be close to 100% efficient, which is why it is used in kettles, stoves, and other appliances. The downside is that the current market price of electricity is considerably higher than that of burnable fuels, and hence can be expensive to run. An interesting side note is that the vast majority of the electricity your appliances use within your home ultimately ends up as heat that helps heat your home.

Electric Infrared Heaters
Targeted heating that needs careful management

• Pros: Cheap to install, heat specific areas directly
• Cons: Can cause damp problems if used incorrectly

The efficiency of infrared heaters is similar to that of storage heaters and very close to 100%. The reason it uses less energy compared to storage heaters is that it can often be timed and targeted better.

It is worth noting that other building issues can occur with infrared heating, as people tend to heat the building less to save costs. A common one we see is colder spots where the heat isn’t targeted, creating condensation and damp in these areas. Another issue is owners turning the heating on when they are in the building and then off when leaving, commonly trapping moisture inside. With no heating to keep the water in the air, it condenses on surfaces and can create mould. 

In certain scenarios, it can be a great heating scenario, but in the wrong scenario, it can be expensive or create expensive building problems.

Air Source Heat Pumps
Modern, efficient, but needs good installation

• Pros: Lower running costs than gas (when installed properly), government grants available
• Cons: Expensive to install, less efficient in very cold weather

Now we move into the heat pumps, where they really start to show their benefits. Modern air source heat pumps are capable of efficiencies of 400% plus. This means that for every 1 unit of electricity, you will get 4 units of heat out, as the heat pump uses that electricity to extract heat from the air surrounding the building. This is why there is a big push from the Government to migrate to heat pumps. The country has a plan to reduce the emissions it takes to make electricity, and moving consumers to electrical heating systems is a huge part of the country’s net-zero plan. The current issue is that the National Grid is limited in the amount of electricity it can reasonably supply, and electricity is currently expensive. Heat Pumps solve this by reducing the required electricity from the grid, and have now managed to reduce their running costs to below that of gas.

If the Government achieves its goal of reducing the electricity price relative to fossil fuels, then heat pumps will become significantly cheaper to run than boilers.

This is why the Government has the £7500 Boiler Upgrade Scheme grant in place to incentivise switching to a heat pump.

Ground Source Heat Pumps
The most efficient but most expensive to install

• Pros: Low energy consumption
• Cons: Costly and complex installation

As with the cost comparison, the ground source heat pump tops the list of the most efficient heating systems. It is, however, likely to be the most costly and complex to install. The reason it is the most efficient is that during the coldest winter months, the ground is warmer than the air; thus, the ground-source heat pump is more efficient in these months.

Air source heat pumps have been closing the gap quite quickly, and it is conceivable that the efficiency of smaller systems may overtake ground source systems in the not-so-distant future.

Summary

In efficiency terms, the heat pumps hugely outperform their boiler equivalents. They demonstrate the amount of energy available in the environments immediately surrounding our buildings, and it’s clear why this is the heating technology being incentivised by the Government.

In our next and final blog, we’ll examine the emissions of each system to provide insight into how the country can achieve its net-zero targets.

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