I bought a Heat Pump

Mstty

JKenH said:

I am posting this table and source link purely to demonstrate the poor rate of take up of heat pumps in the UK. 

https://www.telegraph.co.uk/business/2023/03/14/heat-pumps-wont-work-old-homes-warns-bosch/

2021 stats I suspect an uplift now in 2023 as every small development round here has them as standard. 

JKenH

Following the very useful link to finding EPC certificates I revisited mine which reflects the position prior to fitting solar panels and installation of 2 A2A wall mounted heat pumps. 

As others have commented the EPC often does not fully reflect the true condition of the property - only what the surveyor can see - the fall back position being the requirements of building regs at the time of construction (1990 in my case). I designed my own house and incorporated extra wide cavities to allow for extra insulation and also installed underfloor insulation. Neither of these are reflected in the EPC. The EPC even states solid floors but the floors are actually floating chipboard on top of insulation. The space heating demand was calculated at 26863 kWh and hot water at 3045 kWh. (That may seem high but the floor area quoted on the EPC is 282sq.m.)

Last year we used approximately 1000 litres of oil and imported 5621 kWh of electricity. That includes 10 months EV charging. We do generate about 5500 kWh of PV and last year self consumed 67%. Needless to say, being off the gas grid, we cook by electricity. 

Prior to installing our solar panels ASHPs and getting the EV we used 6900 kWh of electricity and 1800 litres (approx) of oil. The combination of solar and ASHPs has made a massive difference to our energy imports. The installation of ASHPs enables to run our oil fired CH at a low temperature very sparsely and top up the main rooms we use (kitchen and lounge) as required. We also have an open fire in our sitting room which burns wood grown on site. Most of our hot water is covered by our solar diverter (iBoost). 

I believe the A2AHPs and iBoost would be an excellent fit with a heat pump as we would not be totally reliant on the heat pump for heating and could probably get by with our existing radiators. I doubt any HP installer would be prepared to quote on that basis and would insist on ripping out all our radiators (all 18 of them). 

We currently have a Worcester Greenstar 18/25 condensing boiler installed in 2006 which we had serviced last year for the first time since 2008. It must be getting near the end of its days but the guy who serviced it gave me a print out saying it was 98% efficient so I am in no rush to replace but seriously thinking about a heat pump next time round. With electricity prices as they are and oil currently about 70p/litre, though, I just can’t make the sums add up. 

Reed_Richards

At current fuel prices I reckon LPG is the cheapest fuel, then heating oil, with (air-to-water) ASHPs and mains gas about in equal last place (I don't know about storage heaters).  We have to hope that electricity prices are anomalously high at present or attempts to make a green future out of running cars and domestic heating on electricity aren't going to work.

Harvs94

I'm currently looking into whether to get a heat pump under a goverment scheme. I would be switching from oil and a fairly new Grant Vortex 21kw external boiler, installed in 2020. 

As a guide this is my workings;

10,000kWh ÷ 0.9(boiler effiency) = 11,111 kwH energy demand.

11,111 ÷ 10.35 = 1073ltr (Oil Required)

1073 x 0.63 = £675 (Cost of oil per annum based on average my average oil price over 12 months) 

10,000 ÷ 3.65 = 2739

2739 x 0.33 = £903 (Cost of heat pump per annum based on my current tariff)

This however doesn't take into account the electrical running cost of the oil boiler, the added insulation measures (top up loft from approximately 100mm, cavity wall, and room in roof) which would be installed before the heat pump, or the electricity generated from solar which would be installed following the heat pump(approximately 10 panels if we match a neighbour).

The oil boiler is also higher kW at 21 in comparison to the ASHP on offer, varying from 7-17kW IIRC. So I assume the ASHP should be cheaper to run per hour than the boiler?

We don't use much oil or power between myself and my other half over the year, and I feel that surely after the insulation is installed it couldn't not be cheaper in terms of running costs. The measures would bring the house from a low F to a B on the EPC. 

The entire first floor is room-in-roof to some degree and the un-insulated vaulted ceilings are a killer in the summer and winter. 

akwexavante

My home is a 1926 2 bed end terrace ex council house which was heated by propane. 1st floor rooms are partly into roofs pace, slopping corners to all external walls. They were not insulated.

I changed to a gov funded 5kw Daikin heat pump. Best thing I've done. I insulated the room in roof sloped corners to rooms myself with kings pan. What a difference this has made to general comfort and heating costs.

I also now have gov funded solar panels and exporting an average of 18kwh of electricity a day, I'm importing just 3kwh a day at the moment.

The energy I'm exporting over the summer will go a very long way towards paying for my heating this next winter.

I was indecisive about the whole thing but now I can say, just do it, it's a no brainier.

Would I do it if I had to pay for everything myself though, at 60yrs old, probably not. If I was half my age and knew I was going to remain in the home for the rest of my life and could somehow afford it at that age, yes I would. 

Cardew

Harvs94 said:

I'm currently looking into whether to get a heat pump under a goverment scheme. I would be switching from oil and a fairly new Grant Vortex 21kw external boiler, installed in 2020. 

As a guide this is my workings;

10,000kWh ÷ 0.9(boiler effiency) = 11,111 kwH energy demand.

11,111 ÷ 10.35 = 1073ltr (Oil Required)

1073 x 0.63 = £675 (Cost of oil per annum based on average my average oil price over 12 months) 

10,000 ÷ 3.65 = 2739

2739 x 0.33 = £903 (Cost of heat pump per annum based on my current tariff)

This however doesn't take into account the electrical running cost of the oil boiler, the added insulation measures (top up loft from approximately 100mm, cavity wall, and room in roof) which would be installed before the heat pump, or the electricity generated from solar which would be installed following the heat pump(approximately 10 panels if we match a neighbour).

The oil boiler is also higher kW at 21 in comparison to the ASHP on offer, varying from 7-17kW IIRC. So I assume the ASHP should be cheaper to run per hour than the boiler?

We don't use much oil or power between myself and my other half over the year, and I feel that surely after the insulation is installed it couldn't not be cheaper in terms of running costs. The measures would bring the house from a low F to a B on the EPC. 

The entire first floor is room-in-roof to some degree and the un-insulated vaulted ceilings are a killer in the summer and winter. 

Isn't the assumption of an annual system COP; including for hot water, of 3.65 rather high?

Harvs94

Cardew said:

Harvs94 said:

I'm currently looking into whether to get a heat pump under a goverment scheme. I would be switching from oil and a fairly new Grant Vortex 21kw external boiler, installed in 2020. 

As a guide this is my workings;

10,000kWh ÷ 0.9(boiler effiency) = 11,111 kwH energy demand.

11,111 ÷ 10.35 = 1073ltr (Oil Required)

1073 x 0.63 = £675 (Cost of oil per annum based on average my average oil price over 12 months) 

10,000 ÷ 3.65 = 2739

2739 x 0.33 = £903 (Cost of heat pump per annum based on my current tariff)

This however doesn't take into account the electrical running cost of the oil boiler, the added insulation measures (top up loft from approximately 100mm, cavity wall, and room in roof) which would be installed before the heat pump, or the electricity generated from solar which would be installed following the heat pump(approximately 10 panels if we match a neighbour).

The oil boiler is also higher kW at 21 in comparison to the ASHP on offer, varying from 7-17kW IIRC. So I assume the ASHP should be cheaper to run per hour than the boiler?

We don't use much oil or power between myself and my other half over the year, and I feel that surely after the insulation is installed it couldn't not be cheaper in terms of running costs. The measures would bring the house from a low F to a B on the EPC. 

The entire first floor is room-in-roof to some degree and the un-insulated vaulted ceilings are a killer in the summer and winter. 

Isn't the assumption of an annual system COP; including for hot water, of 3.65 rather high?

Perhaps? I wasn't sure which figure would be best. The COP given on the data sheet is only shown for a flow temp of 35degrees which is in the range of 4.5 to 5.5.

I took 3.65 from a calculation guide on YouTube from Heat Geek.

Cardew

Do you have Underfloor heating? If not, switching from oil will need bigger radiators if you want to run at 35c.

Heating domestic hot water will lower your overall COP.

From the information posted on this forum, by those with an ASHP, it would appear that a annual system COP of 3.0 is reasonable estimate.

Reed_Richards

Harvs94 said:

I'm currently looking into whether to get a heat pump under a goverment scheme. I would be switching from oil and a fairly new Grant Vortex 21kw external boiler, installed in 2020. 

As a guide this is my workings;

10,000kWh ÷ 0.9(boiler effiency) = 11,111 kwH energy demand.

11,111 ÷ 10.35 = 1073ltr (Oil Required)

1073 x 0.63 = £675 (Cost of oil per annum based on average my average oil price over 12 months) 

10,000 ÷ 3.65 = 2739

2739 x 0.33 = £903 (Cost of heat pump per annum based on my current tariff)

This however doesn't take into account the electrical running cost of the oil boiler, the added insulation measures (top up loft from approximately 100mm, cavity wall, and room in roof) which would be installed before the heat pump, or the electricity generated from solar which would be installed following the heat pump(approximately 10 panels if we match a neighbour).

I think you are correct in calculating that at current prices for oil and electricity an oil boiler would be cheaper to run that a heat pump and I agree that your assumed CoP of 3.65 is over optimistic unless you have underfloor heating throughout or can install radiators with a very large surface area.  It's hard to predict what will happen to these prices in futurre.  

Additional insulation would reduce your running costs for any form of heating, oil or heat pump or whatever.

Solar panels will help a little but are unlikely to make much impact in winter when a heat pump is using the most electricity.

Harvs94 said:

The oil boiler is also higher kW at 21 in comparison to the ASHP on offer, varying from 7-17kW IIRC. So I assume the ASHP should be cheaper to run per hour than the boiler?

I think you are mistaken here.  The ASHP might be cheaper to run per hour but would be on for more hours than the oil boiler so it evens out.  What will most probably happen is that the oil boiler will cycle more frequently, run for a while then stop because the return water temperature has become too high.  The heat pump, supplying less power, will run for longer periods before the return water temperature gets too high.    

Harvs94

Cardew said:

Do you have Underfloor heating? If not, switching from oil will need bigger radiators if you want to run at 35c.

Heating domestic hot water will lower your overall COP.

From the information posted on this forum, by those with an ASHP, it would appear that a annual system COP of 3.0 is reasonable estimate.

We don't have any underfloor heating.

Supposedly once the insulation is installed they would carry out a heat loss survey to determine the size of the radiators that would need replacing. 

However, I'm now being told that room-in-roof insulation may not be included despite the council website stipulating otherwise, without which I don't believe it would be worth it at all. As a guess 50% of our upstairs ceilings are vaulted room-in-roof, which is probably where all our heat is going.