Domestic Sustainability Systems -Advice Please.

jerby

Hi all.
Just looking for advice on what to do next. I live in a 11yr old, 4 bed bungalow in the SE of Wexford with my wife and daughter. We have underfloor heating run on oil. Just finished paying for my attic & wall insulation, and i am wondering what to do next. I am thinking about an "Air to Water" underfloor running system instead of the oil, (recommended by a user), but as far as i know, there is no grant available.
The other choice would be to get Solar panels in, which would be more affordable at the moment. Should i do one before the other or does it matter? Any other idea's would be great. At present we have a C2 rating, so anything would help. Thanks for taking the time to read this, and as i said any advice would be great. Thanks. Jerry

BryanF

jerby wrote: »

Hi all.
Just looking for advice on what to do next. I live in a 11yr old, 4 bed bungalow in the SE of Wexford with my wife and daughter. We have underfloor heating run on oil. Just finished paying for my attic & wall insulation, and i am wondering what to do next. I am thinking about an "Air to Water" underfloor running system instead of the oil, (recommended by a user), but as far as i know, there is no grant available.
The other choice would be to get Solar panels in, which would be more affordable at the moment. Should i do one before the other or does it matter? Any other idea's would be great. At present we have a C2 rating, so anything would help. Thanks for taking the time to read this, and as i said any advice would be great. Thanks. Jerry

jerry, do the solar thermal panels first. the issue with A t W is that it runs on electricity, and its efficiency reduces dramatically when its cold.. you will also need to keep your backup heat ie probably the oil...

Macha

Definitely solar thermal or PV before atw. In case you're not aware grants here:

http://www.seai.ie/Grants/Better_energy_homes/homeowner/What_Grants_Are_Available/

saibhne

Macha wrote: »

Definitely solar thermal or PV before atw. In case you're not aware grants here:

http://www.seai.ie/Grants/Better_energy_homes/homeowner/What_Grants_Are_Available/

Just in case, I thought it worth mentioning that there are no grants for Solar PV available, just solar thermal.

With regards the OP I agree that solar thermal makes sense to consider next. However you say you have a C2 rating even after getting walls and attic insulation in. Is it possible that your boiler could be upgraded to a more efficient model as well? If so this is a good move in terms of financial savings. You could also check out your windows and see if they need upgrading..

Air to water heat pumps can provide savings but you are essentially heating your house using electricty which is tied into volatile and upwardly mobile fossil fuel prices in Ireland. The move towards heat pumps is predicated on having a cheap supply of electricty in the future, this is fine if you live on the continent which has a healthy supply of nuclear but I would ask questions about the security/price of supply in Ireland.

jerby

BryanF. thanks for your reply. your advice is sound. Just needed to hear it from someone else. i heard that the grants could be reduced in the budget, so i'am getting a few quote's this week. Thanks again, Jerry

jerby

Macha wrote: »

Definitely solar thermal or PV before atw. In case you're not aware grants here:

http://www.seai.ie/Grants/Better_energy_homes/homeowner/What_Grants_Are_Available/

Macha, thanks very much for your reply. i am getting a few quotes this week for the solar panels. Thanks Jerry

pumpkinsoup

Hi jerby,

Have a look at your BER to see if it tells you what are the best next steps.

I'd concentrate on efficiency/ conservation before renewables. Even if you've reinsulated your walls and attic, there may be more you can do to conserve heat. Check if your house is zoned properly, the state of your windows, that the hot water pipes are lagged everywhere including hot press, that the door to the attic is draught-proofed and insulated on top, etc. .

After that you could look at your boiler and see if it's due an upgrade. You can look up the energy rating of your boiler on the SEAI website. I'd say that a 20% energy saving on fuel would be typical for an upgrade of a boiler that's more than 6 years old, so you'll need to do your calculations to see if it's worth your while spending the ca. €2.5k. You could consider a biomass boiler (expensive) as an alternative to oil, or simply installing a wood stove, preferrably with integrated air intake (starting at around €2k installed), while keeping your existing oil system as backup.

If you get solar thermal panels, then make sure to use them to heat your hot water only. Connected to the central heating, the panels will only preheat a tiny bit in winter and you'll still need your oil to bring it up to the right temp. Then you may have the problem of preventing the oil-heated water from making its way back out of your house and onto the roof through the panels. So panels are not an alternative to your oil boiler or a to heat pump. BEWARE: Many (perhaps all?) solar panel providers talk about the 'payback period' of their systems. Ignore this, it's a totally misleading and irrelevant calculation. The calculation completely overlooks the falling value of your investment. Only a return on investment calculation that takes into account the value of your asset is credible - but this is beyond many of them. Anyone who compares their payback period to rates offered in the banks should be shown the door!

Not that familiar with air source heat pumps, you'll find mixed feedback on the internet. I remember working with one in college a long time ago; the evaporator used to freeze up because of the humidity and the COP (efficiency) would drop right off - could have been down to me though! You could try the renewable energies forum on this site for a more informed view. You'll need to switch over to night rate electricity to make it worthwhile. Generally they're installed in new builds with very high levels of air tightness.

Don't even consider PV, the costs are prohibitive. PV generates electricity (badly in Ireland), which isn't consistent with your existing UF arrangement.

quentingargan

pumpkinsoup wrote: »

If you get solar thermal panels.....you may have the problem of preventing the oil-heated water from making its way back out of your house and onto the roof through the panels.

Many (perhaps all?) solar panel providers talk about the 'payback period' of their systems. Ignore this, it's a totally misleading and irrelevant calculation. The calculation completely overlooks the falling value of your investment.

Hi Pumpkinsoup, I agree with your conclusions above, but I would just challenge two things that you say above;

The oil boiler only heats the water in the top of the cylinder. The lower coil, which is heated by solar, is not in contact with this heated water, so it cannot export this heat to your panels. Either way, all solar installations have a one-way valve to prevent this from happening, and providing it is a proper high temperature one, there won't be a problem. This is standard in all pump stations.

I don't agree that payback has to take into account the depreciating value of the panels. Flatplates for example, have a lifespan of about 40 to 45 years. Yes - tubes will have to be replaced after about 20, but with flask systems, that isn't an expensive overhaul.

I would agree that in estimating payback time, many companies over-egg it - the savings depend on the amount of hot water used, the heating system used to heat water in summer, and of course, future energy cost trends. In the next few weeks, payback times will fall by about 18% on that score...