Morning @Brydo this guys calculations when comparing running costs somewhat inaccurate.
The industry standard calculations are based on Coefficient of Performace ratings (COP)
Formula: Total heat demand multiplied by 1, divided by heating effiency, multiplied by price per Kwh.
A rated gas boiler: 6591kw x 1 / 0.92 (92%) x £0.103 per kw = £737.90
C rated gas boiler: 6591kw x1 / 0.85 (85%) x £0.13 per kw = £798.67
5Kw heatpump (cop 3) 1694 x1 / 3 (300%) x £0.34 per kw = £191.98
Based on his figures of 6591kw gas used @10.3p per Kw (£679) and 1694Kw of electric used @34p per Kw (£575)
What he didn’t tell you, is that he has an 18Kw solar PV system with battery storage!!
There is also whats called a Seasonal COP or Seasonal Perfomance Factor that factors in true costs over a year and is was heating engineers design heating systems. This guy has only give 3 months so can’t really calculate.
The average airsource heatpump as his 5Kw arotherm is, can heat hot water to 55c. The use of an immersion heater heats the water to just above 60c, the temperature to kill harmfull bacteria such as Legionella. This guy said he didn’t need to have an immersion heater and refused!! Also you run the risk of not having enough hot water without an emmersion heater.
This guy said too big of a heatpump you run the risk of it cycling – correct. The same applies to, too small of a heatpump will work harder than it should, equally putting pressure on the pump. This guy said he has 12 radiators, previously used for his gas boiler, which suggests 5Kw heatpump is too small for his house!
From 2013 gas boilers were are based on 70c, flow 20c room temp deltaT50, even with older systems working on Dt 60. Even if you have Rads based on the slightly larger Dt 60, based on a coversion factor of 0.79 between them. However a typical heatpump runs on a basis of Delta t 30 or 40!…
Industry standard states it is possible to use existing radiators if you increase the flow temperature of the heatpump, however that defeats the object of having one doesnt it. The norm is to increase the suface area of the rads to allow the heatpump to run at much lower operating temperatures. This guy says he has 12 rads in his house, which were used with his old gas boiler. 12 rads suggest he has a 4bed plus home or he suffers from alot of heat loss (which heatpumps are play a big part in their sie calculation). Either way 5Kw heatpump is too small for his home. You can buy high temp heatpumps (which his isn’t) but again they are far more expensive to run, which defeats the object!!
This guy said far colder Scandinavian contries have heatpumps so why can’t we. We can but, Scandinavian countries have had airtight, full insulated buildings (floors roofs walls) we have not!!
This guy seems the type that will tell a tradesman, in this case heating engineer whats best for his home and has dscounted tradesmen untill someone come along and did as he said rather than whats best!!
It is widley excepted a heatpump works/cost on the basis of the amount of heat energy moved versus the amount of electrical energy used depends on the source temperature and the output temperature, similar to a gas boiler, if its warmer outside you interior doesn’t cost as much to heat up and vice versa…
Compared to modern gas boilers, heat pumps are likely to be a bit more expensive to run unless particular attention is paid to ensuring maximum efficiency of the heat pump in the heating system by using best practice radiator / underfloor heating design and the fluctuation of prices per Kw of gas or electricty (a typical heatpump has 3x more effieciency (300%) per Kw of electric used, however gas is 3 times cheaper than that of electricity)! so you need to think what futurer prices will hold.
If your thinking of installing a heatpump have an accredited company in who can correctly calculate the heat loss of your home and sies for heat needed, rather than listening to someone who isn’t telling the whole story and could be saying the Sky is sky blue pink! Its ulikely the likes of British gas or Octopus will quote you because f the size of your home, as they tend to base their cheap systems on standard 3 bed homes or under. If they did quote you would get it cheaper from an accredited installer. I have seen enough people get ripped of or have something not suitable or needed in my job and I wouldn’t wish it on anyone!
There are also hybrid sytsems available that use a combination of heatpumps and your gas boiler 🙂