PigletJohn - new build heating system?

[shanghaismog]

Sorry to single you out but we´re getting a bit baffled by what´s available out there...

We´re building a new timber frame home and as such need to fulfil the 10% renewable energy criteria. On our plans we have 4m sq solar thermal to heat the hot water. We´re trying to decide what to do for the main heating system and how this ties in.

We´ll have UFH downstairs and would like to use a mechanical ventilation heat recovery system as well as wood burning stove in the living room. If we use a gas boiler to heat the UFH do you think the heat recovery system with electrical UFH in bathrooms upstairs (main & en suite) would be sufficient to heat upstairs? Do you think it´s worth getting a boiler stove for our wood burner to work in tandem with the solar thermal for hot water? Would that be enough, although I guess the gas boiler could top up the water as reqd?

On a totally seperate and much less likely note, we have a company investigating incorporating a GSHP into our piled foundations... What´s your opinion on these? I´ve heard very mixed reports tbh and am a bit wary that we´ll just end up with huge electricity bills.

What would you do given a completely blank canvas? The house will be v well insulated and will have triple glazing. Even the solar thermal can be changed as long as we are using 10% renewable. Any opinion will be helpful as we´re going round in circles!

you will get some heat leakage through the floors, but electric UFH is so expensive to run (energy from electricity costs three times as much as electricity from gas) that I would prefer not to rely on it, so I would have upstairs radiators anyway.

I am very suspicious of the payback on heat pumps.

Solar HW has a good payback provided that the installation is very cheap. Get as tall a cylinder as you can, with a lower coil heated by solar and the upper by the gas boiler.

I have used a heat recovery ventilator, and was disappointed that because it did not create net suction, cooking and bathroom smells and humidity were not sucked out like an ordinary extractor does, your system may be better in that respect.

If your house is v v well insulated, calculate the heat losses, and the energy usage. That will tell you how much it is worth paying for an incremental 10% (or whatever) reduction.

I would go for a multifuel rather than a woodburner. It would be capable of heating the cylinder, but more slowly than a gas boiler. Having several sources of heat has to be skilfully done or the boilers will end up warming each other.

Thank you! If you had a new house what would you install?

I am very unadventurous so would just go for a gas boiler, radiators, and possibly zoning. If it was being built from scratch I might have wet UFH in the ground floor, and possibly the bathroom(s)

I would probably have a large pressurised hw cylinder

Thank you