One type of system I have thought about is a multisplit based inverter heating/cooling system, with cassette units on the wall of each room. I have such a system in the annex and in the loft for heating. On a cold evening it’s cheaper to fire up the loft unit, than turn on the whole house central heating. This type of air to air system, for the right situation and people, has a number of advantages, especially with older housing stock.
- Almost instant heat, unlike the air to water heat pumps
- Heat pumps need to be 30-40C to be efficient..huge rads, expensive underfloor and even then 30 is a bit cool. An air cassette unit running at 30C, or less and is more than hot enough
- Units only need to be on in rooms being actively used, the system can also be auto sensing, zoned and timed etc..
- a room can be heated in 10 minutes
- The main unit can be efficient because it feeds a number of cassettes, so it’s always hot when a new casette comes on line.
- Installation is relatively easy
- The cost is relatively cheap
The cons are that a small gas boiler would be required to heat the water for showers, unless electric showers (which are often not great are used, or perhaps there are some other solutions I don’t know about.
https://les.mitsubishielectric.co.uk/products/air-conditioning/multi-splits/mxz-f-r32-inverter-heat-pump.
This is a typical system and there could be some advantages, for smaller properties 1 system, for larger properties, 2 systems, which gives capacity and redundancy. R32 refrigerant is a little more efficient as well.
https://www.daikin.co.uk/en_gb/product-group/air-to-air-heat-pumps/multi.html
Daikin also do such solutions.
The interesting thing is the above is not being pushed at all…the “only” solution seems to be all or nothing. Big Monoblock heat pump, replacement of all radiators with really big ones (if you have microbore replacement of all pipes). Then it’s got to be on all the time as you can’t heat up a room quickly. Part of the reason could be air to air heat pumps didn’t qualify for the RHI. Also I don’t think air to air heat pumps qualify for the 5K grant either.
All of this is definitely going to push the price paid to the maximum for air to water heat pumps…..
On a warm day or out of the house turn it off…if it gets cold in the evening turn it on. You can also cool rooms as well in summer….where normally the air to water heatpump is as useful as a chocolate teapot.
Installation costs have to be cheaper, you can use 2 units to not have all your eggs in one basket if a unit fails and you can optionally remove all your radiators (or keep them in an emergency) with a boiler that is now only for heating water. You don’t have to have the guts ripped out of your hose and can choose internal casette types to suit your lifestyle.
A much easier/cheaper route to being greener, or perhaps I’m just too thick to understand!
As for cost, see below, although I am sure if you searched around and were buying a whole house system costs would come right down. I reckon way lower than 14K to have a system installed!
