Air Source Heat Pumps

mark11original · 1 July 2016 at 11:19PM

Thanks for the link. I will have a look through it.

Deang_2 · 5 August 2016 at 10:39AM

Hi,

Does anyone have any information on EDG Installations and the daikin air heating system? I've been told I get a government grant to fund a % but the cost comes in at £12000 to be paid over 10 years (finance % included) apparently it will save me no less then 50% on my gas bills and I get £575 a year back from the government for 7 years??? Sounds good but I'm worried it will be a con.

Cardew · 5 August 2016 at 11:09AM

Deang wrote: »

Hi,

Does anyone have any information on EDG Installations and the daikin air heating system? I've been told I get a government grant to fund a % but the cost comes in at £12000 to be paid over 10 years (finance % included) apparently it will save me no less then 50% on my gas bills and I get £575 a year back from the government for 7 years??? Sounds good but I'm worried it will be a con.

What do you mean by ' air heating system'? I assume you mean 'Air Source Heat Pump'?(ASHP) i.e. supplying hot water to radiators and/or Underfloor heating.

It won't save you anything like 50% on your gas bills - in fact it is extremely likely that an ASHP will be more expensive to run than gas CH.

Loads of information on this forum for you to research.

Charlies · 9 March 2017 at 10:51AM

Does anyone have monthly power consumption figures for their Air Source Heat Pump? I know it's difficult to separate from other household consumption but I'm hoping someone might monitor it.

My goal is to compare that (with electricity rates) to our oil use.

Thanks.

Brittal · 23 June 2017 at 4:48PM

I'm looking for some advice. I moved into a new house in November last year. Currently it's supplied by LPG so have central heating and water tank. Around half of the property is solid wall. I'm considering installing solar panels and know that I need to insulate the solid walls.

My dilemma is what is the best way of heating my house. I like the thought of ASHP heating air via air con type units partially for the added bonus of cooling in the summer.
My question is this a realistic economical solution.
From what I've read ashp are not economical vs mains GAS but as I'm on LPG I guess that means they are at least comparible. I've also read about the 24 hour operation but again if I install solar panels at least during daylight hours that should not be an issue.
I need to decide before I insulate the solid walls as I would then simply remove the radiators.

Alternatively I could install a combi boiler but then I think I lose some benefit of solar.

My other dilemma is on size of the solar system based on current usage I've been recommended a 4 kw system but if I go down the aircon / heat pump solution I assume I'd be better served by a bigger system perhaps 5kw.....does anyone recommend solar batteries my concern is that with the investment in battery technology cheaper better batteries are likely just round the corner.

For reference my house floor area is about 1700 sq ft

Sorry for the long post

matelodave · 23 June 2017 at 5:25PM

There are two types of air source heat pump - Air to air, which as you say works like an air conditioner and Air to water which heats water to circulate it around a wet heating system, either underfloor, radiators or fan-coil units. Some are reversible and will cool as well as heat.

Only Air to Water systems are covered by the Renewable Heat Incentive so you wont get any help in the cost of installing an air-air system.

I've got an Air to water system and can give you some info if you want to PM me. We heat a 1350 squ.ft bungalow out in Fenland very successfully and economically but the system was designed from the bottom up.

An air to air system might be cheaper to install and run and doesn't need to run all the time like an air to water system. You'd have to take into account that you'd need a blower unit in each room that has to be heated and an appropriate multi-outlet outdoor unit unless you have lots of individual ones. This is a multiroom split-type capable of running five indoor units https://www.orionairsales.co.uk/mitsubishi-electric-air-conditioning-mxz-5d102va-5-x-25-kw-multi-wall-air-conditioning-240v50hz-613-p.asp

IMO solar power won't help towards heating your home as you'll be heating it in the winter when the days are short, cold and the sun doesn't shine much. Solar batteries wont help either unless you've got a really big one.

My system uses around 2kw a day in the summer when it's just heating water and up to 40kwh or even 50kwh a day in the winter when its freezing cold and heating the house so you'd need a really big battery bank to provide you with enough capacity to run the system for a week or so, if the sun doesn't shine and an even bigger solar array to try and top it up with only 5-6 hours a day of weak or non existent sunlight.

You really need to think it through carefully, do a lot of heat calculations and then try and evaluate the cost of installing and running the various systems to get the best solution

matelodave · 24 June 2017 at 9:14AM

Charlies wrote: »

Does anyone have monthly power consumption figures for their Air Source Heat Pump? I know it's difficult to separate from other household consumption but I'm hoping someone might monitor it.

My goal is to compare that (with electricity rates) to our oil use.

Thanks.

Yes, I've got about 7 years worth of monthly readings and sveral yaers worth of weekly ones

thozza · 24 June 2017 at 2:37PM

Brittal wrote: »

I'm looking for some advice. I moved into a new house in November last year. Currently it's supplied by LPG so have central heating and water tank. Around half of the property is solid wall. I'm considering installing solar panels and know that I need to insulate the solid walls.

My dilemma is what is the best way of heating my house. I like the thought of ASHP heating air via air con type units partially for the added bonus of cooling in the summer.
My question is this a realistic economical solution.
From what I've read ashp are not economical vs mains GAS but as I'm on LPG I guess that means they are at least comparible.

The Notts Energy Partnership has some useful comparison data for different fuel costs:

http://www.nottenergy.com/energy_cost_comparison/

Looking at the current figures, Air Source Heat Pumps are slightly more expensive than LPG using their calculated electricity rate (18.57p/kWh), but at a 'best buy' electricity rate should work out cheaper.

matelodave · 24 June 2017 at 3:01PM

I use a single rate tariff at 11.5p per kwh which gives an effective cost of around 4p/kwh assuming a COP of 3, or 4.6p/kwh with a COP of 2.5.

The COP of a heatpump is dependent on the input and output temperatures and is usually quoted at 7 degrees outside and 35 degrees for the flow temperature.

Most ASHP will give a COP of around 4 or even better at 7/35, however as soon as the outside temperature drops or you try to increase the flow temperatures then the COP will drop.

It's reckoned that increasing the flow temp above 35 degrees will increase your cost by around 2.5% per degree so it pays to make sure that your heating system is optimised for low flow temperatures. Likewise avoid having high hot water temperatures.

Most heatpumps wont get above 50-55degrees unless you get a specific high-temperature unit. To acheive higher temperatures an additional electric immersion back-up heater is used - COP=1.

That's why it's never a good idea to bung a heatpump onto an existing heating system, the existing radiators are sized for a 60-70 degree flow and are therefore incapable of heating the place with low flow temperatures. To get effective heating, the ASHP will need to use the back-up heater unless oversized radiators or fan-coil units are installed.

Brittal · 24 June 2017 at 6:08PM

Thanks for the feedback. My LPG is only 29p a litre so currently I'll be better saving with conventional central heating and I'll avoid the capital outlay. I may switch my attention to energy saving via Heat Genius type smart heating.

Air Source Heat Pumps

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