Heating solution for complete renovation job

declanobrennan

Hi there,

I've posted about this a few months ago (thanks for all the helpful replies) but my situation has changed a bit - I got the keys to the house last month and have builders lined up ready to go. I am looking for some advice on heating my newly bought home - a 3 bed mid terrace , 2 story home in Inchicore, built circa 1936.

The house has being unoccupied for nearly ten years and has being gutted before sale. It needs a complete renovation re plumbing/heating/electrics.. no central heating sytem/boiler in situ.

There is a lean to type extension across half the width of the back - this was used as the kitchen. It’s sub regs now so we are knocking it and replacing it with a full width extension - so excavation and groundwork required here.

The first floor throughout this house composed of 1” thick tongue and groove deal timber sheeting on suspended timber joists. The ground floor throughout this house composed of 1” thick tongue and groove deal timber sheeting on suspended timber joists and tassel plates having underfloor ventilation.


Relevant quantity survey recommendations :

1 -INSULATION -
Attic fiberglass insulation 300mm
Internal walls standard 12mm slabs, ceilings up stairs insulated board 27mm, bathrooms 12mm moisture resistant boards.

2 HEATING SYSTEM: wall mounted gas fired condensing combination boiler linked to the main town gas supply to provide domestic hot water and heating needs of the house.

3 NEW FLOOR: The ground floor to this house is composed of 1” thick tongue and groove deal timber sheeting on suspended timber joists - in an open plan room (which will be open to the full width extension). There is evidence of timber decay and with repair at this time at an approx. cost of €250.00 will suffice for another five to seven years at which stage one could then consider replacement with a new concrete floor at the same time as the rear extension is being replaced. This replaced concrete floor would contain damp proof membrane and underfloor insulation to facilitate underfloor heating (UFH) if required.

4 WINDOWS: The windows to this house are the original deal timber windows casement type single-glazed -to be replaced by moderm windows incorporating double/ triple-glazing

My dilemma:

The rear extension is getting built immediately - as in, excavation to start next week. So we are gonna replace the suspended timber floor with a new concrete floor at the same time as laying the extension floor.

So I just need to decide what heating system to go for. I would like to embrace the most energy efficient and sustainable solution, to do my bit to counter global warming and possibly save some money on bills -so that would be air to water heat pump and UFH (with 4 rads for upstairs bedrooms and bathroom). But I’ve being warned off against it by a plumber who had a look at the site - he said he could do it but if it was his house, he wouldn’t. Basically because it’s an old house.

But with the new double/triple glazing, the new floor, the attic insulation and the internal dry lining - won’t it work just as good?

The other option is the GF combi-boiler feeding UFH (with rads upstairs).

I have done a cursory exploration of Solar PV and IR panels but I'm not convinced the IR panels walk the walk.

Any helpful advice most welcome! Thanks!

MicktheMan

Concerned you haven't mentioned air tightness or ventilation. Both of these are key if you want a low energy house.

The "most energy efficient and sustainable solution" is the one which hardly uses any oil, gas or kWhr in the first place i.e. concentrate on getting the building fabric as energy efficient as possible and then decide how to supply whatever level of heating is required.

Rushing such decisions rarely results in the optimal solutions.

declanobrennan

MicktheMan wrote: »

Concerned you haven't mentioned air tightness or ventilation. Both of these are key if you want a low energy house.

The "most energy efficient and sustainable solution" is the one which hardly uses any oil, gas or kWhr in the first place i.e. concentrate on getting the building fabric as energy efficient as possible and then decide how to supply whatever level of heating is required.

Thanks. I had airtightness and ventilation in mind when I mentioned the new glazing (double / triple) and replacing the suspended timber floor - but yes I do wonder whether that will bring up the airtightness levels to a level that will make a heat pump effective at warming my home.

What are the main issues then that need to be factored wrt the fabric and airtightness/ventilation?

Calahonda52

If you want to get the grant for the heat pump, then the HLI must be less than 2.0
If it were my gaff I would put 200mm insulation in the floor and get EWI done at the same time as the windows, fitting the windows to the outer leaf of the external walls

declanobrennan

Calahonda52 wrote: »

If it were my gaff I would put 200mm insulation in the floor and get EWI done at the same time as the windows, fitting the windows to the outer leaf of the external walls

Thanks!

Firstly, re the floor insulation - is that cos it's better value than pouring a new floor (which will also introduce a DPM and some insulation - not sure how much).

Secondly, I love the redbrick out the front so not keen on EWI. And the back is now gonna be the new extension which will be insulated and triple glazed etc so presumbly EWI doesn't come into play here?

Thanks for that SEAI document - I'll have a read and see how much I can understand but I have being trying to figure out what informs the BER categories so cheers!

declanobrennan

Can I go for cavity wall insulation? The foam stuff injected into the front and side walls?


External walls on rear elevation composed of 9” thick solid concrete block construction. Front elevation external walls composed of 4½” thick solid concrete block inner leaf, 2” cavity with wall ties and 4½” thick facing brick outer leaf. Party wall between this and the adjoining house either side composed of 9” thick solid concrete block construction which creates the appropriate vertical fire separation between this and the adjoining house either side.

declanobrennan

:eek:

MicktheMan wrote: »

Concerned you haven't mentioned air tightness or ventilation. Both of these are key if you want a low energy house.

The "most energy efficient and sustainable solution" is the one which hardly uses any oil, gas or kWhr in the first place i.e. concentrate on getting the building fabric as energy efficient as possible and then decide how to supply whatever level of heating is required.

Rushing such decisions rarely results in the optimal solutions.

Just an update on this which might really help clarify things - the architect is committed to bring the house up to B2 Ber - as per Part L of the regs. He has done up construction drawings with u-values on the insulations, new floor, windows, doors etc.

MicktheMan

declanobrennan wrote: »

:eek:

Just an update on this which might really help clarify things - the architect is committed to bring the house up to B2 Ber - as per Part L of the regs. He has done up construction drawings with u-values on the insulations, new floor, windows, doors etc.

.... and the air tightness target / ventilations strategy are ....?

declanobrennan

MicktheMan wrote: »

.... and the air tightness target / ventilations strategy are ....?

Not sure. Is this architect remit too? Who would test these in the end?
(I assume no point testing now as the house is derelict...)

Thanks for your help

MicktheMan

declanobrennan wrote: »

Not sure. Is this architect remit too? Who would test these in the end?
(I assume no point testing now as the house is derelict...)

Thanks for your help

Ask your arch what the air tightness target is and report back and also how will the house be ventilated.