We are in the process of buying a new house which is a standard 1970's build.
The house needs a number of things doing and some of those are obvious such as double glazing and insulation. The insulation is minimal at present but we plan to do the roof, walls and under the suspended floor. With these we hope to get the house to 'good' levels of airtightness.
But.... then comes the heating system & ventilation.
Part of me would like to go the whole way and buy into the best green solutions but both money and the house style/design are worrying me.
Firstly, the house style issue - we are planning to update a number of the windows to doors in this L-shaped house to really accentuate the outdoor living aspect of this house that already has a glass wall to one side of the L-shape. Therefore, we are hoping to spend a reasonable amount of time with large parts of the house open to the outside.
How does this outside living style sit with the concept of heat recovery ventilation systems? It would seem for large parts of the year it would be working against all those openings?
My second question is probably a common one amongst the British – my experience of air con is bad, draughty, noisy and horrible (I have been known to switch it off even in the tropics because it was so annoying), are these ventilation systems any better?
My next question is to do with costs. If, as I expect, we just cannot afford to go for a non-conventional heat source i.e. ground or air source pump, is it still worth doing things such as underfloor heating or heat recovery ventilation systems? (Remembering that this is a retrofit as so will mean disturbing all aspects of the house to install.)
Thanks for any comments and thoughts
I've passed your questions on to our sustainability expert. While you wait for his response, it's worth reading our main feature on mechanical ventilation and heat recovery (MVHR): http://www.self-build.co.uk/guide-mechanical-ventilation-heat-recovery
We also have a article on retrofitting underfloor heating: http://www.self-build.co.uk/retrofitting-underfloor-heating
Andrew (Build It's Digital Assistant Editor)
Thanks for the links
If you have the doors wide open you probably don’t have the heating system on and you wouldn’t need the MVHR system on either so not to worry. If it’s a concern then you can link a window sensor to the system to auto switch off when it’s open. Live outside as much as you can - enjoy!
The good MVHR systems are silent as long as the fan & motor are located outside the living space (eg in the loft or garage). Probably won’t be supplying cooling - our demand for it is sadly so low in this climate. Your experience is probably of underpowered badly maintained machines located near you running at max 24/7 so not surprised. Heat recovery is very marginal on cost savings - but a whole house ventilation system is useful especially where natural ventilation is limited (1970s) and you are adding insulation which will reduce air leakage so either way make sure you have adequate fresh air especially in bedrooms.
Underfloor heating (UFH) is great (as it gets rid of radiators and runs at a lower temp, emits heat evenly, where you most need it) but in 1970s they often built solid slabs with no insulation and this is a pain to dig up - but you say you have suspended floors so this may be ok. There are also low profile solutions now that require minimal disruption. UFH needn’t be too expensive so take care with quotes.
Nigel Griffiths (Build It Expert)
Thanks Nigel for your answer and thoughts,