UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

rhubarbe

: arty68:

"The Ecodan usually comes with a tank (you can buy it without the tank)just for the DHW the CH is fed directly from the Heat pump.This is one of the reasons I didn't choose an ecodan as you have no backup for your heating."

Yes, Mitsi packaged the Ecodan with a Gledhill Boilermate but fell out with Gledhill and seem to be telling the installers to tell punters that Gledhill have gone bust - I spoke to them last week and they seem very much alive.

Mitsi now package the HU tanksize CP copper unvented Kingspan but this is too big for my installation. Mitsi specify copper cylinders so I could use a McDonald Engineers PowerFLOW 2000 or a Manco cylinder.

"You could just get the ecodan or any other ASHP for your heating and either keep your combi just for hot water or replace your combi with a newer LPG combi or electric boiler.

No, I couldn't. We're doing this exercise because our LPG supplier (and we have just three locally) have gone from £19.00 a 47KG Propane to £45.00 now and both other suppliers are over £54.00. We would rather hammer six inch nails through our feet than pay these highwaymen.

"There are combi like ASHP available in Japan which will be over here sometime in the future so you could wait."

If you mean the EcoCute they are not coming. I am told that: " Hitachi won't be bringing this (Ecocute) into Europe - they cite too high Chlorine content in the water - apparently it becomes "activated" at high temperatures and attacks the welds on the unit internals."


"Are you changing your rads because they will need to be oversized if you want good efficiency?"

I'm playing it by ear. Most of our rads are oversize already. I'll change the ones that aren't if they don't heat the rooms.

@ thills:

"You can get some pretty good undersink instant heaters for water, if your determined to keep the electric showers, have fitted some in the past & they work well if you accept a slower fill rate "

Yes, this is an option I have looked at but I'd need three of them and I rather think I'd be called Luddite.

Thanks very much for your replies.

arty68

You may not like it but without having a tank the LPG would still be cheaper than electric for your hot water, so in money saving terms it wouldn't make sence.

As far as I can tell the problem with Gledhill was the quality but I have no personal experience of them so I could be wrong.

As for the ecocute i believe as the market for ASHP increases they will find a work around but who can say when that will be.

rhubarbe

I know. I have run up against the problem and rather than fight against what is available I think I am going to go for the PowerFLOW 2000 150L heat pump enabled tank.

neas

Its probably been asked bu how efficient are heat pumps compared to gas central heating cost wise?

I.e. i know elec heating is more expensive than GCH... and supposedly heat pumping is 4x more efficnet than elec heating....

But does anyone have a comparison? i.e. how cost effective it is (if at all) etc

rhubarbe

It depends upon more things than you can shake a stick at. Probably against mains gas there isn't much of a saving at UK ambient temperatures.

But - and it's a biggie, read the latest on Feed-in-Tariffs from friendly DECC:

Now that will make ASHP cost way less even than mains gas IMHO.

paceinternet

It depends on many factors, including the weather temperatures at your location and your heating requirements due to life style and insulation.

Over a year a heat pump might average a COP of 3, so in simple energy cost terms, if your electricity is 8p per kwh and gas 3.5p per kwh, then the heat pump will be more cost effective. If your numbers are different, it can go either way.
There are government (RHI) benefits likely to be introduced which will make it more cost effective.
If you have mains gas and existing radiators, then the overall installation cost might be difficult to justify at the moment.

arty68

neas wrote: »

Its probably been asked bu how efficient are heat pumps compared to gas central heating cost wise?

I.e. i know elec heating is more expensive than GCH... and supposedly heat pumping is 4x more efficnet than elec heating....

But does anyone have a comparison? i.e. how cost effective it is (if at all) etc

http://www.nottenergy.com/energy-costs-comparison3

toerag33

Thank you for taking the time to read this long post. I have read all the posts and feel I am more confused now. We have a combi gas boiler supplying our heating and hot water and we would like to replace it with an environmentally friendly option and lower the cost of heating. We want to plan for this hence our looking around just now. We thought a ground source heat pump would meet our needs - after reading all of the posts I don't know!

We have spoken with one company and they proposed the worcester boiler the air one or if a bore is possible a ground source system. This would then just be hooked up to our current radiators. We were given the impression that we would still have constant hot water though we don't think so. The attic has been converted so there is not storage space for a tank up there.

It is a busy house on 3 floors not including the cellar. We have 3 shower rooms and a bathroom which are all used daily. I do a lot of cooking and laundry - about 8-10 loads a week. Currently we have 15 radiators and one room with underfloor heating. We are going to extend the underfloor heating through the ground floor. The house is very well insulated.

I contacted one company who will advise on the suitable options but the cost is about £500. What options would folks here suggest we look at?

Thank you

albyota

Hi toerag33, have a look at the Sanyo ECO CO2 system which heats water to 65 degrees, or the Daikin Altherma HT system which does 80 degrees without electrical backup, next on the list would be Mitsubishi's Ecodan, all very good equipment all with 3 or 5 yr warranty. If the heatloss calcs are carried out properly, these systems will work and you would have a very efficient heating system and plentiful amounts of domestic hot water.

paceinternet

1. You need to get a heat load assessment done for the house and hot water, and be totally honest with what it tells you.
2. Next check the radiator sizes and outputs for each room and consider that if you go to a heat pump running at 50 deg C, the outputs of the radiators will be halved, so will they still provide enough heat?
3. If you want to get the maximum efficiency from the heat pump, it will need to be run as low as 35 deg C, so make sure you get outputs quoted at recomended operating temperatures.
4. Certainly moving to underfloor heating would help.
5. Hot water will need to come from a tank, and will be at lower temperature, so make sure it is able to meet your needs.
6. Ground source will provide more stability in low ambient temperatures, but an air source system should be lower capital cost but may need some auxilliary backup. Your gas boiler could provide that back up if it is still operational.