heat pumps and ventilation

mapboy

I am building a house which is 3000sq ft.There is underfloor heating going in upstairs and downstairs.I am going to use an air to water heat pump.
100mm insulation in sub floor downstairs and 50 mm upstairs.
100mm cavity going to be pumped.
50mm insulated slab on all external walls.
I am going to fill the spaces in the attic between the 150mm joists with
two 75mm foilback insulated sheets.
The going to roll attic rockwool across it.

I do not think i will bother with heat recovery system or aim for any air tightness test results.

I may draught proof around the windows and doors.

I am just trying to be sensible and not go blowing money on every idea out there.

I also may put in a solid fuel stove in the big open plan kitchen just to heat the space and also putting an open fire place in the sitting room.

Any ideas or advice would be greatly appreciated.

fclauson

Couple of points

1 - this will not current building regs
2 - what is your provisional BER for this build

mapboy

Which part is not current regs??

fclauson

100mm in the floor for UFH

Not thinking about air tightness

And I would not separate my insulation in the wall - have it all in one place

Also what is your expected BER and have you considered having a PHPP done

Have you called your U values?

mickdw

mapboy wrote: »

Which part is not current regs??

Most if it.
If you have not got an energy plan of some description done, that is the first thing you should arrange.
I feel you under estimate the energy requirements of the 2011 regs.
An open fire will be difficult and you will be pretty much tied to heat recovery and ventilation system together with a good level of airtightness.
Even your exterior wall spec will need to be looked at.
I'm not an energy assessor but the builds ive been involved with with 2011 regs have been serious.

MicktheMan

mapboy wrote: »

I am building a house which is 3000sq ft.There is underfloor heating going in upstairs and downstairs.I am going to use an air to water heat pump.
100mm insulation in sub floor downstairs and 50 mm upstairs.
100mm cavity going to be pumped.
50mm insulated slab on all external walls.
I am going to fill the spaces in the attic between the 150mm joists with
two 75mm foilback insulated sheets.
The going to roll attic rockwool across it.

I do not think i will bother with heat recovery system or aim for any air tightness test results.

I may draught proof around the windows and doors.

I am just trying to be sensible and not go blowing money on every idea out there.

I also may put in a solid fuel stove in the big open plan kitchen just to heat the space and also putting an open fire place in the sitting room.

Any ideas or advice would be greatly appreciated.

Good luck with that, LOL

Apart from probable compliance issues ...

...after you move into your new house and can't figure out why you are cold and your heating is costing you a fortune, you may want to call somebody like me who tests houses for heat loss. I will test the house and tell you that you should have taken airtightness seriously when building but unfortunately it is too late now and you will always have a draughty house.

mapboy

What's your advice then

MicktheMan

mapboy wrote: »

What's your advice then

Education really:)

Read / research this forum for a start especially concentrating on the building fabric. Get this right and everything else gets a lot easier.

fclauson

also employ the right professionals

grazeaway

mapboy wrote: »

I am building a house which is 3000sq ft.There is underfloor heating going in upstairs and downstairs.I am going to use an air to water heat pump.
100mm insulation in sub floor downstairs and 50 mm upstairs.
100mm cavity going to be pumped.
50mm insulated slab on all external walls.
I am going to fill the spaces in the attic between the 150mm joists with
two 75mm foilback insulated sheets.
The going to roll attic rockwool across it.

I do not think i will bother with heat recovery system or aim for any air tightness test results.

I may draught proof around the windows and doors.

I am just trying to be sensible and not go blowing money on every idea out there.


I also may put in a solid fuel stove in the big open plan kitchen just to heat the space and also putting an open fire place in the sitting room.

Any ideas or advice would be greatly appreciated.

not tryign to rain on your parade but i would recommend seallign teh house as best you can while not going for a passive standard do try to seel the place where you can. a good cheap-ish way to healf do that is to put a rough plaster finsh on teh insode off the walls before you slab it, this will healp seal the jionts in the block work. Teh area around the doors and windows need special attention so if you can seal the gaps as best are you can (i recommed sealign teh outside and the insidewith silicone and expanding foam thenseal teh inside with silicone again. UFH heating for a 3k size house will take a lot of heat so you dont want to waste it.

one draw back of highly insulated houses is that they have poor ventailation so depending on the level of insulation and airtighness a MHRV might be needed.