[Spana]

Over the last few months we've been talking to several companies and getting quotes for a 4kWp photovoltaic system for the house.  We would also like to get rid of our oil fired boiler.

The company we favour the most has been to do a site survey for the panels and recommends changing our old oil fired boiler for an air source heat pump.

On paper the panels make sense financially but i cant get my head round the air source heat pump.  OH is really keen on both.

We don't know anyone who has either the photovoltaic panels or an air source heat pump but the company say they have installed both systems to customers who would be willing to let us have a look.

I know some of you guys are interested in this sort of thing and wondered what you thought.

I'd be really interested in anything you have to say good or bad about both systems.

Thanks

[Gwiz]

I'm dead keen on installing a very minor 12volt solar panel system in our home. We tend to get depressingly frequent power outages here, and it would be interesting to see what we could run and for how long on a small scale system.
As for the air source heat pump, I'm interested but know very little about them. I'd say go and have a look at the ones installed, and see how the owners home/ lifestyle compares to yours. I'd love to hear how the people get on with it, and whether they find they need to have any other type of supplementary heating, and if so, what-and for how long?

[John]

I don't think PV panels make much sense ecologically in the UK but with the feed in tarrifs they may well make economic sense.

Air source heat pumps.. probably better than oil (or LPG) but as you've got land, what about a ground source? Much more consistent especially in really cold weather (OK, I know you're in the warm bit)

Watch out for noise with an air source pump. You may need to house the outside bit to keep the noise down.

[Spana]

Thanks Gwiz and John.

Gwiz, i'm not good with this 'lectric stuff.  Do you intend to store electricity in batteries?

John, my John-OH- wont consider a ground source heat pump altho I think it would be a better system for radiators.  We're going to have a look at some air source heat pumps working and apparently the government will be making some sort of statement about them in April and we've been advised to wait and see what thats about before making any decision. I'm also worried about noise and efficiency.  We had one when our girls  were children to heat a swimming pool and i was never impressed but that was 30 years ago and I'm thinking they must be much improved now.
I quite fancy the PV panels,  we have a good unshaded south facing site to put them.  Is it lack of day light that makes you say they  dont make ecologically sense in the uk or something else? 

[John]

Well ground source pumps are about 4:1 whereas air source are 3:1 but ground source costs more to install - so you pays yer money and yer takes yer choice.

With our northern latitude, amount of cloud cover etc PV doesn't make a lot of sense in terms of power generated to cost incurred. However, the lack of joined up thinking from the government means you can get crazy amounts of money from the feed in tariff. So if you've the money to invest, better than anything else from a financial viewpoint.

Wind power can make eco sense, depending on your location. 

With heatpumps the higher the temperature you want to have inside, the lower the efficiency. They're great for underfloor heating where you are after water temps. around 20 but if you're running with radiators which usually run at 50 or 60 not so good. What you can do is use over-sized radiators or those electric fans (very low consumption) that pull the heat out from the radiator and use those, turning down the water temp.

Also, run for longer at lower temps to keep the house warm rather than the burn / stop system fossil fuel fired boilers use.

How come your John is so anti ground source?

[Spana]

How come your John is so anti ground source?

Well, I've just asked him that and he says hes been sitting thinking about it and now thinks it might be better. 

if you've the money to invest, better than anything else from a financial viewpoint.

It seems crazy to me  and i keeping looking for the catch.  Thats one of the reasons i asked here

[John]

There's always a chance the gov. reneges on the deal in a few years I suppose.

If you've got the room, trees. Willow for chipping into a boiler etc. Efficient, truly green but I don't think you get a grant

[Gwiz]

On our small scale effort, the generated electric would be stored in batteries ready for use when the power fails (often)We wouldn't need to use too many batteries as we are only talking about a need for up to a few hours at a time. One side of our roof faces due south, so would accommodate some small panels quite well.

As an aside, at work we got permission to erect a rather large wind turbine, however, after looking more into the figures, it wouldn't have been cost effective to go ahead with it. We are looking at pv panels though, which produce electric even when it is cloudy (not as much, but enough to be worth while from a PR, feed in tariff point of view) It would certainly help to drop our violently expensive electric bills.
I must find out today if we are going ahead with the plan, it seems to have gone a bit quiet on the news front.......

[John]

I've always been interested in alternative power as it was known but have to say that self-generating is not the best use of government funding. Combined heat and power in the cities would save far more CO2 and increased efficiency heating like ground source heat pumps on grant would make sense. Plus yet more insulation.

The trouble is most of us don't want to spend to save money in the future. Put £100 in a bank and maybe you get £2 interest in a year. Put £100 into insulation and it might be £10 or even £50 off the fuel bills but people don't see a line on the gas bill saying "Extra Insulation Saving"

I've seen in Norway and Austria just how efficient insulation can be - minus 20 outside, plus 20 inside and just a teeny tiny radiator in the room. Thanks to treble glazing, 2 feet thick walls filled with insulation etc

[mumofstig]

wandering off topic slightly, but our old housing stock (I'm thinking victorian terrace here) cannot easily be insulated to those high standards, and that's a huge problem for the future

[John]

One tip - if you've a high ceiling you can use a fan to drive the heat back down. It's amazing how much difference in temperature there is at the top.

[gillie]

"One tip - if you've a high ceiling you can use a fan to drive the heat back down."

I have always been puzzled about this.  Surely by 'driving the heat back down' you simply speed up the convection currents so that the heat rises a little bit faster.  You cannot gain anything overall.

[Gwiz]

Ah, but rather than having all the hot air at the top, the fan will circulate the hot air giving a more even temperature over-all.

[John]

I've seen an old carpet inner tube (from carpet shop) with a fan (DIY store around £10) fitted to the bottom in an old flat with 10' ceiling. It was like having a fan heater in the room. I'm sure a neater job, painted etc wouldn't look bad either. The one I saw was a bit of a duct tape nightmare but it proved the concept.

[Trillium]

Gillie, the fans rotate slowly, never fast. The idea is to move the air, not spin it. Every time I start up my wood burner, I switch on my ceiling fan which is set to low, and the heat can easily move to most rooms. Now only if it went around corners into the bedrooms, I'd be SO happy 

Last fall we finally finished doing a heavy insulation of our attic. We packed 12" thick batts across the whole attic, over wood framing and everything except for the outer edges where we allowed air to enter the upper areas to prevent mold and moisture. We've noticed a big increase in warmth and that the furnace turns on less often. Normally we'd be into our 3rd tank of oil by now, but have only just gotten our 2nd tank, so yes, mega saving even doing the attic.