How many heat pumps are NOT eligible for the BUS?


The Boiler Upgrade Scheme (BUS) is now officially live. For those that don’t know, this is the £5,000 heat pump voucher scheme. One of the criteria is that to be eligible the heat pump of choice must achieve a COP of 2.8 in heating mode (there is no limit in hot water) at the design flow temperature. 

For people new to heat pumps and who haven’t read my book (50 Things You Need To Know About Heat Pumps) COP (Coefficient of Performance) is just percentage efficiency divided by 100. A COP of 2.8 means that for every unit of electricity we use, we have to gather 1.8 units from the air in the garden and supply 2.8 units of heat to the house.

If the heat pump is either not on the MCS product register, is less efficient than 280% or doesn’t achieve a COP or SCOP of 2.8 as listed on the MCS database it does not qualify so you won’t get the voucher.

Now let’s imagine I had the time to go on the MCS product database and gather all the COPs of every unit, write them down and put them in an Excel spreadsheet – I could tell some really interesting stories. 

Here is a snippet:

There are 1,177 air source heat pumps on the register. Some units cannot run at every temperature – there are some low temperature units and some that are high temperature. 

If you run your heat pump at a design temperature of 35C, 1,166 heat pumps can achieve this, but only 1,144 of them meet the SCOP of 2.8.

At 45C, 1,149 heat pumps can achieve this temperature and 1,121 are eligible for BUS vouchers.

At 50C, 1,112 heat pumps can achieve this temperature and only 1,077 will meet the 2.8 SCOP.

There are only 111 heat pumps which can reach 60C of which 25 fail to reach an SCOP of 2.8.

In all cases every unit which fails to hit the target COP has been on the MCS database for more than 5 years.

So we can conclude that any heat pump available today will meet the SCOP target of 2.8 and is eligible to get the BUS. The bar has been set very, very low indeed. No one has been thrown under the BUS so to speak.

Now for the fun bit.

Who makes the unit with the highest SCOP?

Who makes the worst SCOP unit?

Who hasn’t released any new units for eons?

Are heat pumps with the new wonder refrigerant, R290 higher COP than those old R32 units?

What effect does running the unit at 35, 45, 55 and 65C make on the SCOP and run cost?

Are splits really more efficient than monoblocs?

I bet you’d love the answers to these questions, but I’m a heat pump consultant and that sort of information isn’t free. If I get time I will write a report and sell it in the foreseeable future, but don’t hold your breath because I’m off on holidays later this week.

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121 kWhs
1 year ago

Whenever a government incentive is placed on something the price seems to go up by more than the incentive! making it a nonsense. Electric cars did the same. I wonder if the expensive approved installers pay to get on the approved lists pushing up their prices too. The poorest people need the cheapest most efficient systems but only the rich can afford them, how is that fair? I think the law needs to change and landlords should be taxed on how efficient they make the homes they rent out, or the value they offer to tenants. I am one of those rich enough to afford my own just not rich enough to help others.

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