There is a wealth of technology that can improve a home's energy efficiency, and several worth considering when making a home heat pump ready. We have ranked our selection by payback — how quickly each pays for itself in energy savings.
Many require a significant upfront investment. But specified correctly alongside a heat pump, they reduce energy use, improve comfort and lower running costs over the long term.
| Technology | Cost | Annual saving | Payback |
|---|---|---|---|
| Wastewater heat recovery | £350–£450 | £150–£200 | 1–2 years |
| Positive input ventilation | £700–£1,200 | Comfort and damp reduction | 3–4 years |
| Bidirectional EV charger | £930–£1,500 | £250–£500 | 3–5 years |
| Solar PV | £6,500–£8,000 | Up to £759 | 6–11 years |
| Home battery | £3,000–£10,000 | Varies with tariff and usage | 7–10 years |
| Wet underfloor heating | £5,400 (30m²) | £250 vs radiators | 9–10 years |
| Mechanical ventilation heat recovery | £3,000–£10,000 | Around £415 | Around 19 years |
Costs and savings are estimates and vary considerably by property, usage and installer. Correct as of August 2026.
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The heat pump ready series A nine-part guide to preparing your home, produced with low-carbon homes architect Colin Usher. |
Cost: £350–£450 fully installed | Saving: £150–£200 a year | Payback: 1–2 years
The fastest payback on this list, and the least well known.
Wastewater heat recovery captures heat from the hot water going down your shower drain and uses it to pre-warm the cold water coming into the house. A coiled heat exchanger wraps around the waste pipe below the shower; incoming mains water passes through the coil, picking up heat from the water draining away, before it reaches your hot water cylinder.
It needs plumbing into your bathroom and connecting to the hot water cylinder you will be installing as part of the heat pump system — so the sensible time to fit it is during or shortly after the heat pump installation.
There is a second benefit worth knowing about. If it is installed at the same time as the heat pump, you may find you need a hot water cylinder as little as half the size you would otherwise require, which reduces the capital cost of the heat pump installation itself.
Cost: £700–£1,200 fully installed | Running cost: £5–£10 a year | Payback: 3–4 years
Positive input ventilation (PIV) raises the air pressure inside the house slightly, so warm air reaches every corner and stale, damp air is pushed out through whatever gaps remain. A unit sited in the loft draws air in, filters it, and distributes it into the home. Some units include a low-power heater to temper the incoming air.
Payback here is less straightforward than for the other technologies, because much of the benefit is not a metered saving. It comes from:
For a relatively modest investment, PIV delivers noticeable results. It is the system Colin and Jenny Usher recommend first to anyone reporting black mould spots — our guide to draught proofing your home includes a case study showing why.
Cost: £930–£1,500 fully installed, excluding the car | Saving: £250–£500 a year | Payback: 3–5 years
A bidirectional charger lets your electric car act as a home battery for a fraction of the cost of a dedicated one. You set aside part of the car's battery for household use — perhaps 10kWh — and keep the rest for driving.
Because a car battery is far larger than any domestic battery, it can power a home for a couple of days during a serious power cut, depending on capacity and demand. Like a home battery, it stores solar generation or cheap overnight electricity and releases it at peak times.
We assess payback on the charger alone rather than the car, since you would have the car for transport regardless. At around 5% of the value of a £30,000 EV, the charger is not a major outlay.
Not all EVs support it. Manufacturers including BYD, Ford and Nissan have incorporated bidirectional charging, but it remains a developing technology. When you come to replace the car, the new one may not be compatible with your existing charger.
Your driving pattern matters. If you commute and the car is away during daylight hours, it cannot store your solar generation the way a home battery would. In a two-car household, the car that stays home can do this job while the other commutes.
Cost: £6,500–£8,000 | Saving: up to £759 a year | Payback: 6–11 years
Solar PV is usually the first technology an energy-conscious household considers. The outlay is considerable, but it pays for itself two ways: by powering the home directly so you buy less from the grid, and through the Smart Export Guarantee, under which your supplier pays you for what you export.
It will also run the heat pump during daylight hours.
To get the most from it you have to change how you use energy. If you are out during the day, set the washing machine and other major appliances to run from mid-morning when generation picks up. If you have an EV and you are at home, charge it from the sun.
If you are not at home during the day, consider a home battery or a bidirectional EV charger to store what you generate.
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Always use a certified installer Make sure your installer is MCS or Flexi-Orb certified. This covers components and workmanship, and it is what makes you eligible for the Smart Export Guarantee. It also matters for conveyancing when you sell, and many home insurers will not cover a system installed without it. |
Our guide to solar panels and heat pumps covers this pairing in detail.
Cost: £3,000–£10,000 | Payback: 7–10 years
Usually installed alongside solar PV, a home battery stores energy and releases it when you need it most. It makes most sense if the house is empty during the day, when most solar generation happens.
The arithmetic is straightforward. Rather than exporting surplus solar at the Smart Export Guarantee rate of roughly 5p to 20p per kWh, you store it and use it later, avoiding buying grid electricity at around 26p per kWh.
There is a second way to save even without solar. On a time-of-use tariff, electricity is cheaper when demand is low and more expensive at peak times. A battery lets you charge cheaply overnight and draw from it during expensive periods — a practice known as peak shaving.
Installing alongside solar PV saves money by using a single installer. As with solar, the installer must be MCS or Flexi-Orb certified.
Our guide to home batteries goes into sizing, chemistry and tariffs.
Cost: around £5,400 for 30m² | Saving: £250 a year against radiators | Payback: 9–10 years
Wet underfloor heating uses water pipes embedded in the floor screed, and it suits a heat pump particularly well. It runs at much lower temperatures than radiators, and it turns the entire floor into the heat emitter — giving the large surface area that a heat pump's lower flow temperature requires.
Since most homes need radiator upgrades for a heat pump anyway, underfloor heating is worth considering as the alternative rather than as an extra.
Installation is disruptive. You will need to re-floor, and probably adjust doors, skirting boards and wall fixings because the floor level rises. For that reason it is really only recommended as part of an extensive refurbishment.
Cost: £3,000–£10,000 fully installed | Saving: around £415 a year | Payback: around 19 years
MVHR is a step up from positive input ventilation in both capability and cost. Here is how it works:
In hot weather it helps too, extracting warm stale air from upstairs rooms and replacing it with filtered fresh air.
The Centre for Sustainable Energy suggests a system of this kind can cut energy costs by around 25% a year. On a typical annual bill of £1,664 that is roughly £415, which against an average cost of £8,000 gives a payback of around 19 years.
The long payback is why it sits at the bottom of this ranking — but like PIV, much of its value is in keeping the whole home free of damp and cold spots, which makes it a healthier place to live. MVHR performs best in a home that has already been made properly airtight; in a leaky house much of the recovered heat escapes anyway.
Heat pumps work best maintaining a steady indoor temperature rather than repeatedly reheating a cold house. Smart controls help you do that, and they cost far less than anything else on this page.
Around £35 to £80 per unit. Thermostatically controlled, they shut individual radiators down once a room reaches temperature. The more expensive models are Wi-Fi controlled, so you can warm the house before you get home.
Where radiator valves control a single radiator, a thermostat controls a whole zone. A Hive thermostat costs around £119 and works via a hub costing around £70. With one hub and two thermostats you can heat upstairs and downstairs separately.
Hive claims each thermostat can save around £167 a year, which would pay back the hub and thermostat in just over a year. That is a manufacturer's figure, and real savings depend heavily on how your heating was controlled before — a household already using a well-set timer will see far less.
You can put the heat pump itself online. These controllers are generally made for specific models, so they are usually specified as part of the original purchase.
The main advantage is optimising how the heat pump runs — leaving it off while you are at work and bringing it on an hour before you return, for instance. Combined with zoned controls, the savings compound.
Cats are destructive creatures, and this extends to your thermal envelope. Like a letterbox, a cat flap is a poorly sealed hole in a door.
The useful tip here is to look for the lowest U-value rather than the highest price. Some expensive flaps making strong draught-proofing claims have surprisingly poor U-values. The best we have seen is not the most expensive: the PetSafe Extreme Weather flap retails at around £69 with a U-value of 1.2, while others costing considerably more come in at 3.0 or worse.
A microchip-operated flap holds itself closed and will not blow open in wind — and has the side benefit of stopping the neighbourhood cats letting themselves in for dinner.
Start with the quickest payback that suits your home. Wastewater heat recovery pays for itself in one to two years, and positive input ventilation in three to four — both far faster than solar panels or MVHR. If you are already installing a heat pump, prioritise anything that can be fitted at the same time.
No. A well-insulated, draught-proofed home with a correctly specified heat pump already performs efficiently. These technologies improve comfort, cut running costs, or make better use of cheap electricity. Most homes benefit from a selection rather than all of them.
A heat exchanger fitted around your shower waste pipe that captures heat from draining water and uses it to pre-warm incoming cold water. It costs £350 to £450 installed and saves £150 to £200 a year, making it the fastest payback of any technology in this guide.
In many homes, yes. Smart thermostats, radiator valves and heat pump controls reduce unnecessary heating and match your heating to your routine. Savings are modest individually but add up, and the outlay is small. Treat manufacturer savings claims with some caution.
Many can be retrofitted, including smart controls, home batteries, positive input ventilation and bidirectional EV chargers. Wastewater heat recovery and underfloor heating are far more cost-effective when installed during major renovation work or alongside the heat pump itself.
It depends what you want from it. At around 19 years the financial case alone is weak, but MVHR keeps a home free of damp and cold spots and delivers constant filtered fresh air. It works best in a home already made properly airtight; in a leaky house much of the recovered heat is lost anyway.
A heat pump is only one part of creating a low-energy home. Once the building fabric has been improved through insulation and draught-proofing, carefully chosen technologies reduce energy use further, improve comfort and lower running costs.
Some offer rapid payback and others are long-term investments. The best approach is to pick the measures that match your property, your lifestyle and your budget — and where possible, to install them at the same time as the heat pump, when the disruption and the access costs are already being paid for.
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Next in this series 8. Home Batteries: Storing Energy for Lower Running Costs — sizing, tariffs, and whether a battery earns its place without solar. Previously: 6. Wall insulation options |
Produced with Colin Usher, low-carbon homes architect. Last updated: 3 August 2026.
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