Eco home installers in Cardiff

Local buying guide for Cardiff

This is a summary of the main points from our UK buying guides, set out for homeowners in Cardiff. Prices are UK averages for 2026, so quotes in your area can come in higher or lower. Use the figures to judge whether a quote is sensible, then read the full guide before you sign anything.

Heat pumps

• An air source heat pump for a typical UK home costs about £8,000 to £15,000 before any grant.
• The Boiler Upgrade Scheme in England and Wales takes £7,500 off an air source heat pump, which brings the cost for many homes down to roughly £500 to £7,500. Your installer must be MCS certified and applies for the grant on your behalf.
• Insulation comes first. A heat pump works best in a home that holds its heat, so loft and cavity wall insulation often make the system smaller and cheaper to run.
• Ask for a room by room heat loss calculation, not a rule of thumb. The installer should also check whether your radiators are big enough for lower flow temperatures.
• A heat pump is a good replacement for many homes but not all. Very small flats, or homes with no outside space, can be difficult.

Read more: Air source heat pump buying guide

Solar panels and batteries

• A typical 3 to 4 kWp home system costs £5,000 to £10,000 installed, and around £7,500 for 4 kWp. Savings are usually a few hundred pounds a year, and payback is commonly 7 to 10 years.
• South facing and east-west roofs do best. A north facing roof makes roughly 30 percent less electricity.
• A 5 kWh battery adds roughly £3,000 to £4,500. It lifts the share of your own solar power you use from about 30 to 40 percent up to 60 to 80 percent, so it makes most sense if you are home during the day or are on a time-of-use tariff.
• The Smart Export Guarantee pays you for power you send back to the grid. Rates are set by each supplier, so compare them.
• Most homes can fit solar without planning permission, but listed buildings and conservation areas usually need consent first.

Read more: Solar panels buying guide

Insulation

• Loft insulation is the cheapest upgrade most homes can make. At the recommended 270mm depth it costs roughly £500 to £1,200, saves around £350 a year and can pay for itself in under two years.
• Cavity wall insulation costs about £1,000 to £2,500 for a typical semi and saves around £300 a year. Have the cavity checked first with a borescope inspection (about £50 to £120). It is not suitable for every wall, especially in very exposed or coastal spots.
• Ask for the 25 year CIGA guarantee on cavity wall work, and keep the paperwork for when you sell.
• Solid walls need external or internal wall insulation instead. It costs more, so get several quotes and check that the installer is TrustMark registered.

Read more: Loft insulation buying guide | Cavity wall insulation buying guide

Other services listed here

• Boilers: any gas work must be done by a Gas Safe registered engineer. Ask to see the card and check the number on the Gas Safe register.
• EV chargers: look for an installer registered with a competent person scheme such as NICEIC or NAPIT, and ask whether your fuse board and supply can cope.
• Biomass heating: you need space for a flue and fuel storage, and in a smoke control area the appliance must be an approved model. Check with your council first.
• Smart controls: a smart thermostat and room by room controls are one of the cheaper ways to cut heating waste, but they work best on a system that is already balanced.

Grants and support in Wales

• The Boiler Upgrade Scheme applies in Wales and gives £7,500 towards an air source or ground source heat pump.
• Nest, the Welsh Government scheme, offers free advice and, for eligible households, home energy improvements.
• ECO4 helps eligible low income households with insulation and heating, and some councils run their own schemes too.
• Schemes open and close, and the rules change. ECO4 and the Great British Insulation Scheme were due to end in March 2026, so check GOV.UK for what is open now before you rely on any grant.
• Insulation and heat pump grants usually require an assessment first, and the work must be done by a registered installer. Never pay anyone who offers a grant "on your behalf" without checking it on the official scheme website.

Read more: ECO4 scheme guide | Home Upgrade Grant guide

How to check an installer in Cardiff

• Ask for the right registration for the job: MCS for heat pumps and solar, FENSA or Certass for windows and doors, Gas Safe for boilers, TrustMark for insulation and wider retrofit work. Then check it on the scheme's own website instead of trusting a logo.
• Read the most recent Google reviews, not just the star rating, and look at how the company answers complaints.
• Get at least three written quotes that list the products, the brand and model, the total price including VAT, and a start and finish date.
• Ask how your deposit is protected. An insurance backed guarantee is the safest, and you should never pay the full price in advance.
• If you sign a contract at home you normally have a 14 day cooling off period. Keep your copy and read the cancellation terms.
• Ask to see a recent job nearby and, if you can, speak to the homeowner.

Questions to ask on every quote

• Who will do the work, your own staff or sub-contractors?
• What exactly is included: removal and disposal of old units, making good, decorating, scaffolding?
• What guarantees come with the product and with the workmanship, and who backs them if the company closes?
• How long will it take, and what happens if the price changes part way through?
• Will you handle the certificate or notification to building control, and when will I receive it?