Heat pump suitability in a cottage

mr572012

Im currently upgrading a late 1800's cottage with triple glazed windows, 100mm external insulation, 100mm kingspan insulation on a flat roof and packing the attic with rockwool.
I'm looking into an air to water heat system with aluminium radiators. My problem is floor insulation. I have the screed taken out but at some stage a subfloor with steel was put in and i'd really rather not have take this out for depth. The ceiling heights are already quite low so I can't raise the floor.
80mm is the depth I have to work with from subfloor to base of doors.
My question is what is the thinnest screed I can put in to allow for insulation and will this depth be adequate for a heat pump to run correctly?
Thanks in advance.

BryanF

Thin insulation will be expensive. 2-3 layers of Aerogel would probably suit the heat pump, that’d equate to say 80-100mm PIR(haven’t done the math)

is the 80mm including floor finishes ie tile/timber?

Generally screeds are min 50mm, but there are specialist products that may reduce this a little.

mr572012

BryanF wrote: »

Thin insulation will be expensive. 2-3 layers of Aerogel would probably suit the heat pump, that’d equate to say 80-100mm PIR(haven’t done the math)

is the 80mm including floor finishes ie tile/timber?

Generally screeds are min 50mm, but there are specialist products that may reduce this a little.

Thanks for the reply, 80mm is top of screed, sorry should have specified. Is there a ballpark figure for price of aerogel? The house is only 85 square metres of floor space but as you said I'd imagine aerogel wouldn't be very budget friendly.

sydthebeat

are you applying for a grant??

the 'technical advisor' route is worth following even if you are not...

mr572012

sydthebeat wrote: »

are you applying for a grant??

the 'technical advisor' route is worth following even if you are not...

I was told that I would need to put 150mm external insulation on the house to be eligible for the heat pump grant but I can't do that due to overhang restrictions. No harm to involve a technical adviser i suppose. Thanks for the response.

Yellow_Fern

I am not expert on heat pumps but dont skimp. When they are badly set up or dont match the building heat pumps can be a nightmare

descol

The Efficiency of the Heat Pump will be reduced and therefore electricity bills will rise Technical Advisers recommendations on U values are followed