Central and water heating options for renovation of 1960s house?

BL

Hi all,

I am an architect, recently returned from several years abroad. I know, my timing is wonderful.........Having recently discovered boards.ie, I must first say there is a fantastic wealth of knowledge and information on these forums, very impressive.

Anyway, I am beginning the design process for a renovation of a 1960's semi detatched concrete block house. Its not rocket science - just plenty of retrofit insulation, new windows and doors, take down a few internal walls, new finishes, new kitchen etc.

The one area I'm unsure of is what to recommend for a central heating and domestic hot water system. The existing house has no provision for heating, besides fireplaces. So we're starting with a clean slate really, when it comes to heating the house and providing hot water.

I'm not particularly knowledgeable on the topic of heating and plumbing, but my gut instinct is to go for a fairly standard, oil or gas burning system, with an efficient boiler. I would love to do something more adventurous, but with my lack of knowledge, I am reluctant to recommend anything - especially given the sheer mass of conflicting info to be found on all of these technologies.

Both myself and my client are interested in renewable energy, particularly solar, but the impression I get is that it doesn't quite cut it in the Irish climate. Circa 50% of domestic hot water requirements seems to be the best that can be expected from such a system. This is really just a small fraction of overall energy use, and not really significant enough to spend a lot of time worrying about at this point.

I realise that oil and gas prices are bound to rise over the medium to long term, but is there a viable alternative in this case? It seems only technologies that can provide a large chunk of the space heating requirements of the house are really going to make a significant difference. As far as I can tell, geothermal is the only truly renewable source of space heating - and this is much more expensive than a traditional system and works better with underfloor systems, which we will not be able to install in this house.

I would greatly appreciate any concise advice on this topic, including alternative technologies. I am conflicted as to whether my inclination towards dismissing solar technology makes me coolly rational or just lazy/short sited?!

PS The house is a three bed semi, circa 1100 square feet, and will have just one permanent inhabitant when completed

Evergreen

Hi BL, welcome home

Have you considered a decent wood pellet boiler with a solar thermal link up on the hot water cylinder? There is a huge range of boilers on the market ranging from don't touch with a barge pole to needing a very fat wallet so I would recommend that you do a lot of research on them.

If you PM me I can give you some information on a nice system that is 97.5% efficient with a lot of stuff such as circulation pump, expansion vessel, return riser and split heating/hot water cylinder flows

Regards,

sinnerboy

BL before you look to how to heat a building - look to how to reduce the heat demand

Insulate as much as you can

Achieve the best air tightness that you can

If you can insulate externally - do that . The current Construct Ireland ( get it in Easons ) has a good article on an end of terrace which was externally insulated . 200mm rockwool + render should cost around €100/m2

If you can't insulate externally be carefull to not to over insulate internally - and make sure the wall can breath to the internal . Again the current CI contains an excellent article outlining the risks in great detail . This article from an earlier issue is worth a carefull read through

http://constructireland.ie/Vol-4-Issue-5/Articles/Sustainable-Building-Technology/Ecological-renovation-moves-F-rated-hollow-block-house-up-to-A3.html

Try to achieve an air tightness performance of Q50/5 or better ( budget €5k ) and install a heat recovery ventilation system ( budget €5-7k )

look here for guidance on air tightness

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18749,en.pdf

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18752,en.pdf

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18753,en.pdf

Look here to select an HRV unit

http://www.sap-appendixq.org.uk/search.jsp

Persuade your client to appoint a BER assessor to work with you to give calculated advice for different spec options - take the guesswork out of it . Budget €500-700 - only use a BER assessor who is also an architect or architectural technician . Look here

http://193.178.2.42/SearchAssessors.aspx

Sorry to fly in the face of your OP - my own opinion is that renewables are expensive with poor return on investment. Get your heat demand down and install an A rated gas boiler . Look here

http://www.sei.ie/Your_Building/BER/BER_Assessors/Technical/HARP_Database/Boiler_Search_Page/

For the fireplace - look to install a room sealed gas fired fire . Or better still wood stove . Either way don't leave the flue open - excessive ventilation heat loss

.

Retro-Fit

Passive standard retrofitting guidelines:

http://www.sei.ie/Publications/Renewables_Publications/Passive_House_Retrofit_Guidelines.pdf

BL

Thanks guys,

Sorry for the late response, this job has been very much on the back burner for a couple of months.

Those were really helpful responses. The links have some fantastic info.

I'm definitely going to concentrate on all the aspects of energy conservation as outlined by sinnerboy. As for the solar, I could take it or leave it - if the client really wants to go with it then that's fine with me.

One other thing I wanted to pick your brains about. Do you think it is a good idea to retrofit underfloor heating in a suspended timber floor construction? I've seen a few details of how it can be done online, and it seems plausible enough. Also opens up the possibility of going the geothermal route....

Its bound to be a bit more expensive and a bit more hassle to retrofit the underfloor, compared to a standard heating system with radiators. But seen as there is currently no central heating at all, all options are on the table. We're also a bit limited for wall space in the living areas, and fitting in the radiators will be a bit of a pain.

If anyone knows of any successful or unsuccessful installations of underfloor heating into a suspended timber floor construction, I'd be very interested to hear some details.

Thanks again guys!

sinnerboy

I have successfully used UFH in upper level timber floors .

It is hassly - but do-able - to install - you have to create a floor in the floor - i.e. support ply boarding off battens fixed side on the the joists - then insulation and screed between joists

BUT .....

A nice architectural opportunity exists - budget permitting - to give the internal ground floor spaces some elevation - by ripping out the suspended timber floor and installing a concrete floor ( + UFH ) . Timber floor is usually 2 steps up from ground - concrete may be reduced to only 1 step up .

Points to watch
- extra step to foot of stairs
- window cills - may need reducing
- door heads - can be nice to leave as is providing door proportions aren't distorted

Pull it off and the architectural improvement internally is well worth it