Air source heat pumps, advice
Discussion
Hello,
Can anyone give me any pointers on these fellas:
http://www.nu-heat.co.uk/heat_pumps.html
My folks are considering getting an air source heat pump in their new bungalow. After reading lots of bumf on the savings, it is still quite difficult to decide whether they can realistically meet some of the claims.
I know the longer you keep it, the better the return, but all im after is knowing whether or not annual heating bills will be cheaper or not.
Cheers
Can anyone give me any pointers on these fellas:
http://www.nu-heat.co.uk/heat_pumps.html
My folks are considering getting an air source heat pump in their new bungalow. After reading lots of bumf on the savings, it is still quite difficult to decide whether they can realistically meet some of the claims.
I know the longer you keep it, the better the return, but all im after is knowing whether or not annual heating bills will be cheaper or not.
Cheers
The rest of the heating system should be designed to work with it - heat pumps are better when producing rather lower temperatures than traditional boilers. If the bungalow is being built with radiators, they need to be sized appropriately. Underfloor heating is best.
The good news is that under current government proposals (still being reviewed), such a system would be liable for a subsidy which should amount to a payment each year for 18 years. You'd have to do the maths, but it might amount to a £100-£200 quid a year.
The good news is that under current government proposals (still being reviewed), such a system would be liable for a subsidy which should amount to a payment each year for 18 years. You'd have to do the maths, but it might amount to a £100-£200 quid a year.
A mate has Panasonic air source heat pumps fitted in his house, and I've been amazed at the heat they chuck out, even when the temperature is well below zero eg -10C it was damn hot. This is in Sweden btw.
He claims, and I have no reason to doubt him as he's fairly reliable in my experience, that their power usage to heat output is as claimed.
To my mind the problem with his installation is that the heat output comes in the form of hot air, and then you have to circulate it round somehow. I guess it must be possible to integrate it with a hot water pumped system as it looks in the linked website.
There are some people round the corner with a similar intallation and I recall the problem with their original installation that condensate from the operation was not properly dealt with and until modification tended to freeze outside one of the property entrances.
Another mate has a ground source heat pump, and he went down this route as he needed a new boiler, the cost of the new boiler was less than the installation of the ground heat pump system, the drilling cost a fair bit, but now it's working it's bloody ace. Constant cheap background heat. There are rules iirc about how close you can install a ground source heat pump to aother system. I digress.
Anyway, I know it sounds mad, but to reiterate I can verify that the air source stuff mentioned whacks out some damn warm air even when the outside temperature is quite low. It seems amazing that the pump is using less power than you would need to generate the same amount of heat by just electrical heating but it seems to work.
You can also operate them in a sort of aircon mode, or at least the air output ones apparently. Never seen that done, when it wa sthat hot we just jumped in the pool / river / lake.
HTH, not a very scientific answer, sorry for that.
He claims, and I have no reason to doubt him as he's fairly reliable in my experience, that their power usage to heat output is as claimed.
To my mind the problem with his installation is that the heat output comes in the form of hot air, and then you have to circulate it round somehow. I guess it must be possible to integrate it with a hot water pumped system as it looks in the linked website.
There are some people round the corner with a similar intallation and I recall the problem with their original installation that condensate from the operation was not properly dealt with and until modification tended to freeze outside one of the property entrances.
Another mate has a ground source heat pump, and he went down this route as he needed a new boiler, the cost of the new boiler was less than the installation of the ground heat pump system, the drilling cost a fair bit, but now it's working it's bloody ace. Constant cheap background heat. There are rules iirc about how close you can install a ground source heat pump to aother system. I digress.
Anyway, I know it sounds mad, but to reiterate I can verify that the air source stuff mentioned whacks out some damn warm air even when the outside temperature is quite low. It seems amazing that the pump is using less power than you would need to generate the same amount of heat by just electrical heating but it seems to work.
You can also operate them in a sort of aircon mode, or at least the air output ones apparently. Never seen that done, when it wa sthat hot we just jumped in the pool / river / lake.
HTH, not a very scientific answer, sorry for that.
Air source can provide hot water systems/central heating systems with heat, they're not just hot air blowers, although these exist as well of course. If the whole house (which is why it's perfect for new builds) is designed around efficiency (efficient rads designed for the lower temps or underfloor heating, insulation, solar glass etc etc) then it's very good. If you're retro-fitting you still get efficient cheap heat but maybe not getting the best out of it - but then you have to calculate benefit vs. cost and it just highlights that older houses aren't that efficient.
Once the initial outlay is out of the way then running cost is minimal, you'll get (or they'll get for you) a 30% grant taken off the purchase price. I'd say for an average house with just a conversion to ground/air source you'd be looking at breaking even in 10 years. (Depending on use of course).
As the heat is less than a regular boiler make sure you can live with 50-55 degrees out of one tap rather than hot + cold taps - i.e. water volume.
Finally, remember calculations into how long it takles to recoup your loss is relative to i. use, ii. to oil/fuel price and iii. to the added value of your house if you sell.
Once the initial outlay is out of the way then running cost is minimal, you'll get (or they'll get for you) a 30% grant taken off the purchase price. I'd say for an average house with just a conversion to ground/air source you'd be looking at breaking even in 10 years. (Depending on use of course).
As the heat is less than a regular boiler make sure you can live with 50-55 degrees out of one tap rather than hot + cold taps - i.e. water volume.
Finally, remember calculations into how long it takles to recoup your loss is relative to i. use, ii. to oil/fuel price and iii. to the added value of your house if you sell.
Tuna said:
The rest of the heating system should be designed to work with it - heat pumps are better when producing rather lower temperatures than traditional boilers. If the bungalow is being built with radiators, they need to be sized appropriately. Underfloor heating is best.
^^^ What he said.Not something I'd recommend as a retrofit to an existing property, unless you were planning a major refurb including new windows, insulation, complete replacement of the heating system, radiators and all. Rads will need to be oversized and the water generated by heat pumps is at a lower temperature than normal central heating, so they never gat as hot to the touch and are not as rapidly controllable.
They also really need a high standard of fabric insulation and airtightness to be really viable, which again is unlikely on an older (ie. pre-21st century) existing property.
There are numerous ways of using a heat pump as a source of low cost heat, from a single split system costing under a thousand to install - up to ground source with water pipes in the floor costing tens of thousands.
If you are talking about a house already built then fitting single air sourced unit can be very cost effective, but you have warm air being blown about and it won't really do more than one room.
Best units in the world at present are Mitsubishi Heavy Industry, say an SRK50ZIX, single split system.
Using a heat pump to heat water for a conventional radiator system is a lot more complicated, and with the cost of electricity versus cost of gas in the UK possibly not very cost effective.
If you can provide some more details I can give you some more advice - take a look at www.climatezone.co.nz
If you are talking about a house already built then fitting single air sourced unit can be very cost effective, but you have warm air being blown about and it won't really do more than one room.
Best units in the world at present are Mitsubishi Heavy Industry, say an SRK50ZIX, single split system.
Using a heat pump to heat water for a conventional radiator system is a lot more complicated, and with the cost of electricity versus cost of gas in the UK possibly not very cost effective.
If you can provide some more details I can give you some more advice - take a look at www.climatezone.co.nz
With the RHI finally coming into force Spring 2014 Air Source Heat Pumps will definately start to become more of a way to get payback from renewable sources. Great selection here http://www.urban-energy.co.uk/air-source-heat-pump...
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