Air Source Heat Pump Installation in Milton Keynes
MCS certified design, installation and commissioning across Milton Keynes, Buckinghamshire, Bedfordshire and Northamptonshire — with the £7,500 Boiler Upgrade Scheme grant taken off your price before you pay anything.
What a heat pump installation involves — and what it costs
An air source heat pump takes heat out of the outside air and moves it into your home. In exchange for one unit of electricity it delivers roughly three to four units of heat, which is why it can be cheaper to run than a gas boiler even though electricity costs more per unit than gas. Whether it is cheaper comes down entirely to the design, and that is the part most of this page is about.
We do not publish a headline price, because a heat pump is sized from your home's measured heat loss rather than from its number of bedrooms, and two identical-looking houses can need very different systems. What we do commit to is how the price is presented. Your quotation shows the full price of the installation, the Boiler Upgrade Scheme grant, and the net figure you pay — and you are never asked to fund the grant and claim it back.
£7,500 off, deducted before you pay. The MCS certified installer applies to Ofgem for the voucher in your name with your written consent, and the grant comes off your price. Off-gas-grid homes on oil or LPG can get £9,000 until 31 March 2027. No work starts until the voucher is issued. How the Boiler Upgrade Scheme works.
Will it be cheaper to run than your boiler?
Only above a certain efficiency, and that number is worth knowing before anyone quotes you. Under the Ofgem October–December 2026 price cap, electricity is 26.32p/kWh and gas is 7.97p/kWh. Electricity is about 3.3 times the price of gas per unit, so a heat pump has to be at least 3.3 times more efficient than your boiler just to break even.
Against a gas boiler running at 85% efficiency, the break-even point is a seasonal efficiency (SCOP) of about 2.8. Here is what that looks like for a home needing 12,000 kWh of heat a year:
| System | Efficiency | Energy bought | Annual heating cost |
|---|---|---|---|
| Gas boiler | 85% | 14,100 kWh gas | £1,125 |
| Heat pump — poor design, undersized radiators | SCOP 2.5 | 4,800 kWh electricity | £1,263 |
| Heat pump — break-even | SCOP 2.8 | 4,290 kWh electricity | £1,129 |
| Heat pump — properly designed | SCOP 3.5 | 3,430 kWh electricity | £902 |
| Heat pump — low flow temperature, good emitters | SCOP 4.0 | 3,000 kWh electricity | £790 |
Two things follow from that table. First, a badly designed heat pump costs more to run than the boiler it replaced — the row at SCOP 2.5 is not hypothetical, it is what happens when radiators are left undersized to keep a quote competitive. Second, the gap between a good system and a bad one is bigger than the gap between gas and a good heat pump. That is why we itemise emitter upgrades in the quotation instead of hoping for the best.
If you currently heat with oil, LPG or direct electric, the sums are considerably more favourable than the gas comparison above, and oil and LPG homes off the gas grid may also qualify for the larger £9,000 grant. Figures here are illustrative and based on the stated cap rates and heat demand; your own numbers come from the survey. You can put your own house through the calculator first.
How the installation works, step by step
1. Free survey
We measure the house rather than estimate it: room dimensions, construction, glazing, insulation, existing radiators and pipework, cylinder space, and where an outdoor unit can go. We also run the MCS noise assessment for the nearest neighbouring window and check planning status.
2. Heat loss calculation and design
A room-by-room heat loss calculation to MCS standards sets the size of the heat pump, the flow temperature and which emitters need changing. You get the design, not just a price. Anything the calculation says is needed appears in the quotation as included, excluded or by others.
3. Fixed quotation, grant deducted
Full price, grant, net price. You see all three. Nothing is payable at this stage, and the quotation is valid for 30 days.
4. Grant voucher
With your written consent and eligibility declaration, the MCS certified installer applies to Ofgem in your name. We do not start work, and you do not pay anything, until the voucher is issued. If it is refused, either of us can cancel at no charge.
5. Installation
Two to four days on site depending on scope, with one day without heating and hot water — we tell you which day in advance. Outdoor unit, indoor unit, cylinder, any emitter and pipework changes, and the electrical work, which we do ourselves as a NAPIT registered contractor.
6. Commissioning and handover
The system is commissioned and balanced, the MCS certificate is issued in your name and lodged, manufacturer warranties are registered to you, and we walk you through the controls. Your handover pack includes the commissioning records and the servicing your warranty requires.
When we will tell you not to bother
A heat pump is not right for every house, and we would rather lose the job at survey stage than install something that disappoints you for fifteen years. We will say so if:
- There is nowhere sensible to put the outdoor unit. It needs airflow, a route for condensate, and it has to pass the MCS noise assessment at your neighbour's window. Some terraces and flats simply do not have the space.
- There is no room for a hot water cylinder. If you are on a combi and there is no airing cupboard, loft space or equivalent, that has to be solved before anything else and it is not always solvable.
- The fabric is so poor that the running cost would not stack up. The grant no longer requires you to clear your EPC's insulation recommendations, but the physics has not changed. Sometimes insulation first is the honest answer.
- You want it quoted on the existing radiators to keep the price down. If the heat loss calculation says they are undersized, fitting the heat pump anyway produces the SCOP 2.5 row in the table above. We will not do it.
- You are in Scotland or Northern Ireland. The Boiler Upgrade Scheme covers England and Wales only, and we work across Milton Keynes, Buckinghamshire, Bedfordshire, Northamptonshire and the surrounding counties.
Frequently Asked Questions — Heat Pumps Milton Keynes
It depends on your home's heat loss, not its size in bedrooms, so we do not publish a single figure. What we can tell you is how the price is built: the heat pump itself, the hot water cylinder, any radiators or pipework the heat loss calculation shows are undersized, the electrical work, and the commissioning. The £7,500 Boiler Upgrade Scheme grant is then deducted from that total, and the quotation shows you all three numbers — full price, grant, and the net figure you actually pay. The survey and quotation are free.
No. The Boiler Upgrade Scheme does not work that way. The MCS certified installer applies to Ofgem for the voucher in your name and with your written consent, and the grant comes off your price before you are asked for any payment, including the deposit. We do not start the installation until Ofgem has issued the voucher. If the voucher is refused, either of us can walk away at no charge.
Only if it is designed properly, and we would rather say that than pretend otherwise. Electricity costs about 26.32p/kWh and gas about 7.97p/kWh under the Ofgem October–December 2026 cap — electricity is roughly 3.3 times the price of gas per unit. A heat pump beats an 85% efficient gas boiler only once its seasonal efficiency (SCOP) is above about 2.8. A well-designed system on correctly sized radiators runs at 3.2 to 4.0 and will cost less than gas. A heat pump squeezed onto undersized radiators to keep the quote down can fall to 2.5 and cost you more than the boiler it replaced. The design is the whole job.
Some, usually, but rarely all of them. A heat pump runs at a lower flow temperature than a boiler — typically 45°C instead of 70°C — so each radiator gives out less heat and the ones that were already marginal become too small. The room-by-room heat loss calculation tells us exactly which ones, and they are itemised in your quotation rather than discovered mid-install. We will not quote a heat pump on the basis that your existing radiators are fine when the calculation says they are not.
It needs to be insulated enough for the heat loss calculation to produce a system that works and runs economically — which is not the same as needing to be a new build. The Boiler Upgrade Scheme itself no longer requires you to act on your EPC's loft and cavity wall recommendations; that condition was removed on 28 April 2026. But insulation still changes the size of heat pump you need and what it costs to run, so the survey covers it honestly and we will tell you if we think insulation should come first.
Usually no. An air source heat pump on a house normally falls under permitted development in England, subject to conditions on size, siting and noise — the unit has to meet an MCS noise assessment at the nearest neighbouring window. Listed buildings and some conservation areas are different. We check planning status and run the noise assessment as part of the survey, before you commit to anything.
Most installations take two to four days on site, depending on how much of the heating system is being changed. You are typically without heating and hot water for one of those days, and we tell you which one in advance. Before that there is the survey, the heat loss calculation and design, and then the wait for Ofgem to issue the grant voucher, so plan for several weeks from first visit to commissioning.
They work well together, but not in the way it is usually sold. A heat pump roughly doubles a typical home's electricity use, and most of that extra demand lands in winter when solar generates least. What solar actually does is stop you exporting cheaply in summer and give you a much higher share of self-consumption year round. If you are considering both, they should be sized against each other in one design rather than bolted together. You can run the heat pump calculator or read the full guide.
Depth of Light Ltd is MCS certified for solar PV and battery storage, and your heat pump is designed, installed, commissioned and MCS certified by an MCS certified heat pump installer working with us — which is what makes the Boiler Upgrade Scheme grant valid in the first place. Depth of Light is your contracting party, all payments are made to us, and we remain responsible to you for that installer's work. Your MCS certificate is issued in your name. It is set out in Schedule 5 of our terms.
Book a Free Heat Loss Survey
No obligation, no pressure, and a straight answer about whether a heat pump suits your house. The £7,500 grant comes off your price, not out of your pocket. Based in Bletchley, Milton Keynes — we cover Buckinghamshire, Bedfordshire and Northamptonshire.