Air Source Heat Pumps

Cardew

paceinternet wrote: »

Difficult, but a few things to consider.
1. how efficient your existing gas boiler is.
2. do you feel better with an eco friendly system.
3. where are gas prices going versus electricity prices.
4. a more detailed assessment of your heating and hot water use, particularly in the months when outdoor temperatures are giving a higher COP, may provide some savings. But it would be difficult to justify the capital cost versus doing nothing if your gas boiler is working ok. If your gas boiler needs replacing, then you may get some benefits with the current electricity/gas price relationship.
5. servicing costs: depends if you go with annual gas boiler servicing, and some would say a heat pump only needs periodic cleaning, which you can do yourself or get done for quite a low cost.

Agree with this 100%.

IMO if you have a gas CH system, it would be doubtful if there would be any financial gain in fitting an ASHP - bear in mind that the existing fitted radiators will not be adequate.

In fact with the current low price of oil, I would also personally favour oil CH over an ASHP for a new larger property; albeit oil prices have been volatile.

As several people have reported, as soon as you start having to use electricity to supplement the ASHP any financial gains are quickly erroded.

The other option with a new build is to have warm air ducting to all the rooms, but as pointed out earlier that creates its own problems.

samtheman1k

arty68 wrote: »

Hello,
I'm currently building a house and am trying to decide the boiler type for my heating and hot water.
The new house is not on mains gas so that's out of the window.
There are too many trees on site to have GSHP (bore hole option very expensive)
The lane is too narrow for the LPG tanker.
Which leaves me with Oil,Pellet or ASHP.
My questions are:-

In the real world do they work ?

Is there a good ASHP that will do Heating and hot water that is reasonably priced ? (Danfoss and NIBE seem to be the best but are expensive).

My plan was to have UFH downstairs and rads upstairs is an ASHP suitable for this ?

Any help with the above would be much appreciated .

If the lane is too narrow for a LPG lorry, then it's going to be too narrow for an oil lorry too, and maybe even too narrow for a pellet lorry! How are you getting all your bricks etc delivered to your house that you are building???

Yes, ASHPs do work in the real work and running costs are comparable to gas over the course of a year. If the right system is sized and bought, they will do everything a gas combi boiler will do, but will work better with underfloor heating and/or larger radiators.

arty68

Apparently you can get a smaller oil tanker than LPG tanker in my area, the width of the lane is about 9' or 2.75m in new money.

arty68

samtheman1k wrote: »

Yes, ASHPs do work in the real work and running costs are comparable to gas over the course of a year. If the right system is sized and bought, they will do everything a gas combi boiler will do, but will work better with underfloor heating and/or larger radiators.

Thanks, have you any recommendations on what manufacturers are the best or ones to avoid ?

samtheman1k

arty68 wrote: »

Thanks, have you any recommendations on what manufacturers are the best or ones to avoid ?

I personally have the Mitsubishi Ecodan and am very pleased with it.

paceinternet

If you haven't appreciated the civils involved in a GSHP slinky installation, have a look here:
http://www.youtube.com/watch?v=LFoZj94Ttjg&feature=related
Several others on there as well.
Helps you recognise why air source is an alternative for those that do not; have the space, want the disruption, or justify the cost, of a ground source system. As good as it might be, it is not for everyone!

dalesman99

This site www . nottenergy . com / energy-costs-comparison3 (sorry anti spam stopped me posting the link correctly, you will need to take the spaces out has done a good job of standardising the cost of 1 KWH for various fuels. Looking at the figures it seems to me that electricity is 4 x the price of gas/oil for 1 kwh output. So to be more efficient an ASH would have to have a COP >4, and to justify the cost would need to be nearer 5, or am I missing something?

dalesman99

Also done some investigation on ground source, general advice has been need approx 2 sq m of ground for every 1 sq m of under floor heating, so you need a big garden.

paceinternet

dalesman99, the comparison is not relevant for all parts of the country as it depends on the local energy costs. In our region, you can get second tier electrical units for just over 8p.
However, even using the numbers as posted, the 3rd column from the left takes care of boiler efficiencies, and shows the results in pence per kwh. GSHP and ASHP are 3.5 to 4.5 which is in the same area as mains gas online at 3.9 and kerosene at 4.1.
Does an ASHP average 250% throughout the year? Well, the better ones will do better than this (300 - 350%) when air temperatures are above zero, so you could say they are being pessimistic when some areas of the country get maybe 10 - 30 days below zero, and some of those days may be above zero for part of the day.

richardc1983

Bump as this is possibly usefull for many ppl.