8kW Air Source Heat Pump: Prices & Is It Big Enough?

What Size House Suits A 8kW Unit?

One thing you don't want to do when buying an air source heat pump, is buy one that's too small. 

Heat pumps are only efficient when they work "low and slow". Undersizing your heat pump will cause it to overwork, consuming much more electricity than a larger and more suitable unit would. 

On the flip-side, buying a unit that’s too big is a waste of money. The bigger the unit, the more expensive it’s going to be.

So, what type of property is an 8kW suited to?

In general, you'd expect an 8kW unit to be perfect for any property that: 

The majority of modern, well insulated properties will need around 60 watts of power per m². Accounting for heat loss, a 120m² property is likely to need a heat pump sized at 7.2kW, so a 8kW is well within spec.

Not sure which size heat pump you need? Get a heat loss survey that's inline with MCS guidelines (calculated at -3°C). Assuming your heat loss survey comes in at less than 8kW, an 8kW unit will be suitable.

The above is simply a guideline. Dozens of factors affect the power you'll need for central heating and hot water, as well as how much heat your property loses. These include the likes of: 

• Quality of insulation, as well as how much of your property is insulated
• Ceiling height
• Radiator sizing
• Property air tightness
• Window quality (single, double, triple glazed etc)

We offer free online estimates which include a free heat loss survey. Use our heat pump quote tool here, which will show you if a 8kW air source heat pump is suitable for your property.

6kW vs 8kW

(Source: Vaillant) 

Heat pumps are expensive. The bigger (in kW output) the heat pump, the more expensive it's going to be. 

So, the next question is what's the difference between a 8kW vs 6kW heat pump? Could you "get away" with a smaller heat pump and save some cash in the process?

Typically, you might be able to use a 6kW rather than a 8kW unit if your property: 

For the average UK property, an 8kW heat pump is likely to be much more suitable than a 6kW. 

You can check the most suitably sized unit for your property and get prices on-screen using our heat pump pricing tool here. 

8kW Heat Pump Prices (Installed)

The prices for 8kW air source heat pumps vary, with the majority of the best heat pump brands supplying units for around £4,000. This is the cost without installation.

A typical installation for a 2-3 bedroom house is likely to cost somewhere in the region of £12,000-£15,000, not including government grants. 

But, most households will be eligible for the Boiler Upgrade Scheme. This government scheme allows households to claim a grant of up to £7,500.

So, the overall installation price for a 8kW unit is likely to be in the region of £4,500-£7,500. 
For our installations, we include the following in the installation price: 

As with any installation, there are always variables that affect price. For a 8kW heat pump installation, expect prices to vary based on: 

• Labour rates in your local area (much higher in the south)
• Any additional works needed (multiple radiator or pipework upgrades)
• Property type, size and the quality of the insulation

For a heat pump to be financially viable, you’ll need to access government grants. 

To check whether you qualify for the Boiler Upgrade Scheme (most households do) and can get £7,500 off your heat pump installation, read our guide to heat pump grant eligibility here. 

Best 8kW Heat Pumps

(Source: Ideal Heating)

There are dozens of high quality 8kW air source heat pumps available in the UK. Of those, our favourites are:

• Vaillant aroTHERM Plus
• Daikin Altherma 3
• Ideal Logic Air

The Daikin Altherma is a premium high efficiency option, typically sitting at the higher end in terms of price. 

With a SCOP (Seasonal Coefficient of Performance) sitting at above 4, it's over 400% efficient. Essentially, for every 1kWh of electricity that it consumes, it's able to produce 4kWh worth of heat. 

Competing with the Daikin Altherma is the Ideal Logic Air. Ideal Heating is a leading brand in the heating space, often offering a similar quality product to the likes of Worcester Bosch, but at a much lower price. 

Generally known as a heat pump that's easy to install, this converts directly into a low cost installation. Typically, we'd expect an Ideal Logic Air 8kW installation to be £1,000 less than some other leading brands.

Finally, we have the Vaillant aroTHERM. This is the ideal unit for those looking for high flow temperatures. Utilising R290 refrigerant, the aroTHERM is able to hit flow temperatures of 75°C whilst still maintaining a high SCOP/COP rating. 

For further reading, we’ve got a guide covering various heat pump reviews here. 

Use our clickable heat pump pricing tool here. There, you'll be able to see which one is the best deal now, as well as which is the most suitable for your property.

Expected Running Costs

Running costs for an 8kW heat pump will vary based on: 

• Your electricity tariff and therefore, cost per kWh 
• Hot water and heating demand
• Your heat pump's efficiency (based on a COP or SCOP rating)
• Quality of your home's insulation

For small 2-3 bedroom properties that are modern and well insulated, expect to pay somewhere in the region of £600-£1,000 per year. This is comparable to the average cost of running a gas boiler. 

Heat pumps aren't best suited to homes that have poor insulation. For homes with poor insulation or single glazed windows with draughts, expect the cost of running a heat pump to be closer to £1,000-£1,500 per year. 

Essentially, getting a heat loss survey before installing a heat pump is important. This helps to determine exactly how energy efficient your home is and if it's suited to a heat pump. 

Use our heat pump quote tool here, which can estimate the heat loss for your property. 

Or, speak to one of our heat pump experts here. 

For a detailed guide, jump over to our page covering ASHP running costs here. 

FAQ

Will an 8kW pump heat my house?

If your home's heat loss survey is less than 8kW at -3°C, then a 8kW unit will be suitable.

Typically, a 8kW heat pump is suitable for small 2-3 bedroom houses that are in the 90–130m² range. Alongside this, you'll need to live in a highly efficient home (EPC of C or better). 

To confirm the exact size heat pump you need, you'll need to get a heat loss survey. We provide a free heat loss survey as part of our estimate. 

Will an 8kW heat pump provide hot water?

Heat pumps provide both heating and hot water. For hot water, you'll need a cylinder installed if you don't have one already. 

A high quality heat pump will be able to consistently provide water at a flow temperature of 50°C, with some units such as the Vaillant aroTHERM hitting flow temperatures of 75°C.

How efficient are air source heat pumps?

Leading heat pump manufacturers generally supply units with a SCOP of 4 or higher. This means for every 1kWh of electricity they use, they'll provide 4kWh of heat (they're 400% efficient). 

Efficiency of your unit will depend on factors such as: radiator sizing, property insulation, flow temperature and outdoor temperature.

Do I need planning permission for a heat pump installation?

Small units in the 6kW-16kW range generally don't need planning permission. Planning permission is generally only needed for large scale commercial installations. 

However, you’ll need to abide by certain installation rules. As an example, you can't fit a heat pump within 1m of your property's boundary.

You'll also want to check with your local council if you live in a listed building or a conservation area. 

Can I use my existing radiators?

Yes, but it’s not advisable. Heat pumps work at much lower temperatures than boilers. To maximise efficiency, larger radiators will be needed.

Ready to see how much your heat pump installation is going to cost? Use our free heat pump quotation tool here. 

Got questions? Speak to one of our heat pump experts here.