Renewable energy: Solar vs heat exchange pumps etc

(11 Posts)
DarkBlueEyes Mon 11-Jul-16 17:15:06

Hoping someone will have some good advice here!

We have not long moved to a bloody cold house with an indoor pool, all heating is gas. OMG I nearly died at the bills as I stupidly believed what the agent said about heating the pool.

We are exploring other ways to heat our house as we're about to do a massive renovation. One company have recommended air source heat pumps and solar PV to generate electricty. The air source should heat our pool and sort our hot water and underfloor heating, the PV panels should provide nearly all our electricity needs (12 panels from memory).

My plumber says air source heat pumps are very noisy and ground source heat pump would be better.

Any advice or guidance would be really, really appreciated, as I am floundering around. Thank you.

DarkBlueEyes Tue 12-Jul-16 17:49:24

Anyone?

foresttrees2 Tue 12-Jul-16 18:00:03

MIL just had a heat pump for a pool fitted. It's really quiet you can't hear anything! She has been really pleased with it!

foresttrees2 Tue 12-Jul-16 18:00:49

I think a ground one may be a lot more expensive? The installation would be harder?

PigletJohn Tue 12-Jul-16 18:25:10

"the PV panels should provide nearly all our electricity needs "

Ha ha ha.

On sunny days they will produce more than you need. On rainy or cloudy days when you need the tumbledrier and maybe a fan heater they may produce next to nothing. They will only power your lights during the day, not at night when you need them. You can't save up the electricity, so if Friday was sunny, and you are washing and drying on cloudy Saturday, you will have to pay for full-price electricity. Equally if you use your oven or dishwasher after about 4pm.

If you have any electric heaters, the panels will only contribute on sunny days; not during short cloudy winters days.

If you heat your water with gas, there is no point buying a solar controller to run an immersion heater, because gas is so cheap that it will not repay the cost of the controller (the adverts might show you a payback assuming you have no gas, and use electricity which costs about four times as much).

Solar panels can get a reasonable output, but it is only the subsidy that makes it worthwhile. I am hoping that the cost and efficiency will over time improve so that they are a paying proposition without needing subsidy.

Air source heat pumps may frost up and stop working in cold weather.

Heat pumps do produce more electricity than you put in, so may be worthwhile. I don't know how long they last or the maintenance costs

DarkBlueEyes Tue 12-Jul-16 19:12:38

Piglet John That's interesting. We were planning on getting battery storage to store the electricity so it could be used at night. I'll ask about the frosting of the air source, that's a really good point, thank you.

The idea of the heat pump is to heat the hot water, not to use solar to do it, if that makes sense, but the solar would just generate electricity which apparently we can sell back to the grid.

Thanks for replying everyone, it's really helpful when you are starting with a zero knowledge base!

DarkBlueEyes Tue 12-Jul-16 19:12:41

Piglet John That's interesting. We were planning on getting battery storage to store the electricity so it could be used at night. I'll ask about the frosting of the air source, that's a really good point, thank you.

The idea of the heat pump is to heat the hot water, not to use solar to do it, if that makes sense, but the solar would just generate electricity which apparently we can sell back to the grid.

Thanks for replying everyone, it's really helpful when you are starting with a zero knowledge base!

PigletJohn Tue 12-Jul-16 19:29:32

There are some big lithium batteries coming out, but they are expected to cost thousands of pounds.
Have you seen price, size and capacity?

Depending which part of the country you are in, you might receive a subsidy and estimated payment totalling around £600, but it depends how big, what output, orientation, age and date the contract started. The installer should have provided an estimate which will be more or less accurate.

Older ones produce less but have a higher subsidy rate.

Lighteningirll Wed 13-Jul-16 07:24:10

My solar panels have been in nearly two years we also have an optimiser which trickles excess solar to the immersion heater (ie heats the hot water). We also have open plan downstairs and a log burner. The FIT payments cover the vastly reduced gas and electricity bill. I set hot water to off in April on the timer and rarely have to boost it and the heating is only on for half an hour every day on winter mornings. The initial outlay (£7,000ish) will be paid back in around seven years but for us (capital rich/income poor) it was more about reducing bills. I would recommend solar panels, even with the current reduced FIT payments if your goal is reducing bills.

minijoeyjojo Wed 13-Jul-16 09:05:23

We have just installed a ground source heat pump and spent ages researching it so I think I have a relatively good idea of the pros and cons.

An air source heat pump is a good option for heating a pool, assuming you only want it heated in the summer months. They are very good then, sadly in the winter they are much less efficient which makes them less useful for heating a pool all year round or your house in the winter. I'd be surprised if you'd make a saving on this vs gas for heating your whole house.

Ground source heating is a much more reliable way of heating your house through the winter. However they cost a rather lot to install, especially if you have to do a borehole. How big is your plot? An added cost can be the requirement for a three phase electricity supply of your GSHP is more than about 25kw.

Again with solar panels, the battery technology is a fantastic concept, but very new on the market. As such they are incredibly expensive so I'm not sure of the cost to benefit ratio of one. Plus they massively cut the subsidy for solar panels at the beginning of the year so it's not such a good deal anymore - although saying that the panels themselves are now much cheaper.

Irrespective of the heating supply, one of the best things you can do is to insulate your house. Have you considered putting in more insulation? Has the pool got a really good cover? Ensuring that you utilise the heat you already have most efficiently should probably be your first thing to do. Neither a ground or air source heat pumps will work well in a poorly insulated home.

To be honest gas is usually the cheapest method of heating your house, if we had gas we probably wouldn't have bothered with the GSHP (environmental issues aside) as the initial outlay is likely to still be significantly more than we'll ever get back under the RHI.

PigletJohn Wed 13-Jul-16 14:43:03

I agree with Lighteningirl that it is a better bet if you have money in the bank doing nothing. With interest rates negligible, and forecast to drop further to mitigate the Brexit recession, and the Pound dropping in value, a future interest stream becomes more attractive, especially if it has a degree of inflation linking.

Solar Panels have been dropping in price, but of course they are imported, so the 16% drop in the Pound will not be helping.

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