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FAQs

Air Source Heat Pump

An air source heat pump (ASHP) is a renewable heating system that extracts heat from the outside air, even in cold weather, to warm your home and provide hot water. It works similarly to a fridge but in reverse, transferring heat into your property.

An air source heat pumpworks by using a refrigerant to absorb heat from the outside air. It compresses the refrigerant to increase the temperature and then transfers that heat to your home’s heating system, such as radiators, underfloor heatingor a hot water cylinder.

Air source heat pumps are highly efficient, even in the UK’s cooler climate. They can operate effectively in temperatures as low as -15°C. For every unit of electricity used, an air source heat pump can generate around 3 to 4 units of heat, making them much more efficient than traditional heating systems.

Yes, air source heat pumps are a renewable and low-carbon heating solution. While they do require electricity to operate, they produce far more energy than they consume. If powered by green electricity, their environmental impact is further reduced.

Yes, air source heat pumps can reduce your energy bills, particularly if you are replacing older electric, oil, or LPG heating systems. Savings depend on factors such as your home’s insulation, current heating system, and energy tariff.

Yes, the UK government offers financial incentives through schemes like the Boiler Upgrade Scheme (BUS), which provides grants of up to £7,500 to help cover installation costs. Additional local grants may also be available.

The cost of installing an air source heat pumptypically ranges between £7,000 and £14,000, depending on the size of the system and your property. While the upfront cost may seem high, financial support and long-term energy savings make it a worthwhile investment.

Not necessarily but it is recommended. Homes with good loft, walland floor insulation, as well as double-glazed windows, will benefit the most from this type of system.

Modern air source heat pumps are designed to be quiet, with most producing a noise level similar to a standard fridge. Noise levels usually range from 40 to 60 decibels and can be minimised by correct installation and placement.

With proper maintenance, an air source heat pump can last for 15–20 years or more. Regular servicing helps to ensure efficiency and longevity.

In most cases, air source heat pumps are classed as permitted development and do not require planning permission, provided they meet specific criteria regarding noise levels and placement. However, it’s always best to check with your local council.

Yes, but radiators may need to be larger to work efficiently with an air source heat pump, as heat pumps operate at a lower temperature than traditional boilers. Underfloor heating is an excellent match for air source heat pumps.

An annual professional service is recommended to keep the system running efficiently. Contact us to arrange your annual service with one of our trained engineers.

An air source heat pumpsystem requires space outside your home for the outdoor unit, which is typically about the size of a standard air conditioning unit. The heat pump should be situated so that air can flow freely into it so sufficient clearance around the unit is required. Inside, you’ll also need space for a hot water cylinder if you don’t already have one.

Yes, when installing an air source heat pump, a heat pump-specific hot water cylinder must be used. In most cases your existing cylinder will not be suitable.

Yes, but older properties may need additional insulation or larger radiators to maximise efficiency. Heat pumps perform best in well-insulated homes, so assessing and upgrading insulation is highly recommended.

Typically, it takes between 2 to 5 days to install an air source heat pump, depending on the complexity of the project. A site survey beforehand will help determine the timeline.

Solar

Solar PV (photovoltaic) is technology that converts sunlight directly into electricity. A solar PV system consists of panels mounted on your roof (or occasionally ground-mounted), an inverter that converts the electricity into a form your home can use, and usually a monitoring system so you can track generation. Unlike solar thermal, which heats water, solar PV generates electricity you can use to power anything in your home — lights, appliances, an EV charger, or even a heat pump. Any electricity you don’t use is either stored in a battery or exported back to the grid.

Solar panels contain photovoltaic cells made from silicon. When sunlight hits the cells, it knocks electrons loose and creates a flow of direct current (DC) electricity. An inverter then converts this into alternating current (AC), which is what your home’s appliances use. The electricity powers your home first; any surplus is either stored in a battery or sent to the grid through a Smart Export Guarantee (SEG) tariff, earning you credit from your energy supplier. Panels work whenever daylight is present — they don’t need direct sunshine to generate.

Solar panels work well in the UK. While we get less direct sunlight than southern Europe, modern panels are designed to generate from diffuse light, so they still produce meaningful amounts on cloudy days. A typical 4kWp system in southern England generates around 3,600–4,200 kWh per year — roughly enough to cover a significant portion of an average household’s electricity use. Panel efficiency has also improved steadily; most modern domestic panels are 20–22% efficient, compared to around 15% a decade ago. Orientation and shading matter more to overall output than the UK climate itself.

Yes, significantly. Every kilowatt-hour of electricity you generate from solar displaces electricity that would otherwise come from the grid, which still includes a mix of gas and other fossil-fuel generation. A typical 4kWp domestic system saves roughly 1 tonne of CO₂ per year. Over its 25+ year lifespan, that adds up to around 25–30 tonnes of emissions avoided. The manufacturing footprint of the panels themselves is typically offset within the first 1–3 years of use, meaning the vast majority of a system’s lifetime is net-positive for the environment.

Savings depend on your system size, how much electricity you use during daylight hours, and whether you have a battery fitted. A typical 4kWp system in southern England saves £300–£700 a year on electricity bills through self-consumption, plus a further £75–£375 a year from the Smart Export Guarantee (SEG) for electricity sent back to the grid. Adding battery storage lets you use more of what you generate rather than exporting it, pushing savings higher. Most systems pay for themselves within 6–10 years and continue generating for decades after that.

Yes, several support routes exist. Solar installations currently qualify for 0% VAT until 31 March 2027, saving around 20% on installation costs — this applies automatically through your installer, with no forms to fill in. The Smart Export Guarantee (SEG) pays you for any electricity you export to the grid, with rates varying by supplier. Lower-income households may qualify for free solar through the ECO4 scheme (running to December 2026) or the Warm Homes: Local Grant. Some local authorities also offer top-up grants, so it’s worth checking what’s available in your area before installing.

A typical 4kWp domestic solar PV system costs around £6,000–£8,500 fully installed, including panels, inverter, scaffolding, and certification. A larger 6kWp system is usually £8,500–£10,500. Adding battery storage typically adds £3,500–£6,000 depending on capacity. Prices vary based on roof complexity, panel type, and the specific components chosen. The 0% VAT rate currently applies to domestic installs until March 2027, which is already factored into most quotes you’ll receive.

A south-facing roof is ideal, but not essential. East or west-facing roofs generate around 80–85% as much as a south-facing one, and a split east-west setup can work well because it spreads generation across the day — better matching typical household use. North-facing roofs are generally not recommended. What matters more than orientation in many cases is shading: a clear, unshaded roof will outperform a south-facing roof that’s overshadowed by trees or nearby buildings. We’ll assess all of this during the site survey.

A properly installed solar PV system shouldn’t damage your roof. Panels are mounted on brackets that attach to the rafters, not the tiles themselves, and weatherproofing is added where any fixings penetrate the roof covering. A professional installer will assess whether your roof is structurally sound before quoting — older roofs occasionally need minor repairs first. In many cases, the panels actually protect the section of roof underneath them from weathering. If you’re planning to replace your roof soon, it’s usually best to do that before installing solar.

Solar panels themselves typically last 25–30 years, and most manufacturers offer performance warranties guaranteeing at least 80–85% output after 25 years. Inverters have a shorter life — usually 10–15 years — and will likely need replacing once during the system’s lifetime. Batteries, where fitted, typically last 10–15 years too, with their own separate warranties. With minimal maintenance, a well-installed system will keep generating reliably for decades, and many early UK installations from the 2010s are still performing close to their original output.

For most homes, no. Solar PV falls under permitted development rights, meaning you can install panels without planning permission provided they don’t project more than 200mm from the roof surface and don’t sit above the highest part of the roof. Listed buildings, properties in conservation areas, Areas of Outstanding Natural Beauty, and World Heritage Sites have stricter rules and usually require permission. Flat-roof installations and ground-mounted arrays also have specific requirements. We’ll check all of this as part of the quotation process so there are no surprises.

Yes, though it depends on the property. Older homes often have suitable roofs for solar — structural checks may be needed if the roof hasn’t been replaced in decades. Listed buildings and homes in conservation areas face more restrictions: panels usually can’t be fitted to front-facing elevations, and planning permission or listed building consent is generally required. In-roof (integrated) panels and slate-style solar tiles are sometimes accepted where standard panels aren’t. We’re happy to advise on what’s likely to be approved before going through the planning process.

Solar panels need very little maintenance. Rain naturally cleans most dust and debris off the glass, so cleaning is rarely needed except in very dusty or pollen-heavy areas, or if birds nest nearby. The inverter and overall system performance should be checked periodically — most modern systems include a monitoring app that lets you spot any issues early. A professional inspection every 5–10 years is sensible to check fixings, cabling, and inverter health. Other than that, there are no moving parts to service and nothing to refuel.

Each kW of solar PV needs roughly 5–6m² of roof space, so a typical 4kWp system needs around 20–24m² — roughly the area covered by 10–12 panels. A 6kWp system needs closer to 30–36m². Alongside total area, the shape of the available space matters: a single clear rectangle is ideal, but installers can work around chimneys, roof windows, and multiple planes. Any shading from nearby trees, buildings, or chimneys will affect performance and should be assessed during the site survey.

Panels still generate on cloudy days, though at reduced output — typically 10–25% of bright conditions depending on cloud density. At night they don’t generate, so your electricity comes from the grid or from a battery if you have one fitted. A battery stores surplus daytime generation for use in the evening, which is when most households use the most electricity. Without a battery, you’ll still benefit from solar during the day but rely on the grid outside daylight hours. Pairing solar with a battery is what most homeowners choose to maximise their savings.

Yes. Batteries can be added to an existing solar PV system at any point. AC-coupled batteries connect to the household supply separately from the solar inverter, making retrofits straightforward with most systems. If you’re installing solar now but not sure about a battery, it’s worth asking your installer to fit a battery-ready or hybrid inverter, which makes adding storage later simpler and often cheaper. Battery prices have come down significantly over recent years, and many homeowners choose to add one once they’ve seen their solar generation patterns.

A typical domestic solar PV installation takes 1–2 days on site. Scaffolding usually goes up the day before the install and comes down a day or two after. Before installation, there’s normally a site survey, system design, and notification to your Distribution Network Operator (DNO) — altogether, the full process from signing off a quote to having a working system is usually 4–8 weeks. Battery installs don’t typically add much time and are often fitted during the same visit as the panels.

Install specific

For an air source heat pump (ASHP) installation, we typically allow around five days from start to finish. This includes everything from the initial setup to full commissioning and handover.

During this time, our team will handle the removal or integration of any existing heating equipment, install the new heat pump and associated components and ensure that all electrical and plumbing connections are completed to the highest standard.

Once the system is fully installed, we’ll carry out thorough testing and commissioning to confirm that everything is running efficiently and safely. Finally, we’ll complete a full handover, showing you exactly how to use your new system and ensuring you’re completely satisfied before we leave.

During the installation process, your heating system will be turned off for the duration of the works, which typically takes around five days. However, we always plan the installation carefully to minimise any disruption to your comfort.

You will only be without hot water for approximately one day, usually towards the end of the installation when the new system is being connected and commissioned. We’ll keep you informed throughout the process and do everything we can to ensure a smooth transition, restoring your heating and hot water as quickly as possible.

As part of the installation process, your old boiler will be safely disconnected, removed, and taken away from your property. We ensure that all materials are recycled or disposed of responsibly, in line with environmental regulations.

Our team handles the entire removal process for you, so there’s nothing you need to worry about — we’ll leave your property clean, tidy, and ready to enjoy your new, energy-efficient heat pump system.

Once your new heat pump has been installed, our team will provide a full handover and demonstration to ensure you’re completely confident in how it operates. We’ll walk you through the key functions of the system, including how to adjust your heating settings, manage the thermostat and optimise efficiency for comfort and energy savings.

As part of our process, we carry out a detailed heat loss calculation to MCS standard MIS 3005 D, which ensures your system is correctly sized and configured for your home. This means your heat pump will perform efficiently and effectively from day one.

We’ll also leave you with clear, easy-to-follow documentation and are always available for aftercare support if you have any questions once you start using your system.

Not always. It depends on the type of system we install and the age and compatibility of your existing thermostats.

If your current thermostats are modern and compatible with the new heat pump system, we may be able to integrate them without any issue. However, in some cases, we’ll recommend installing new smart or programmable thermostats to ensure you get the best efficiency, comfort and control from your new system.

Our team will assess your existing setup during the survey and advise you on the best solution for your home.

If your installation requires new radiators, any old radiators that are removed will be taken away and responsibly recycled. We ensure all materials are disposed of in line with environmental standards, helping to reduce waste wherever possible.

Our team will handle the removal process safely and efficiently, leaving your home clean and ready to enjoy your upgraded heating system.

In most cases, no additional building works are required as part of a standard air source heat pump installation, unless this has been agreed in advance.

 
However, air source heat pumps do require a solid, level base for the outdoor unit. In some situations, depending on the location and condition of the site, minor building work may be necessary to create or prepare this base.
 
Unless otherwise agreed, arranging this groundwork remains the responsibility of the customer, though our team is happy to advise or help arrange any necessary preparation to ensure a smooth installation process.

Booking your annual heat pump service is simple. You can call our Service Department on 01273455695 or email us at service@agreeneralternative.co.uk to arrange a convenient date and time.

Regular servicing helps keep your system running efficiently, extends its lifespan and ensures continued compliance with MCS and manufacturer warranty requirements. Our experienced engineers will carry out a full performance check and make sure everything is operating at its best.

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