Air to Water

KCross

Deleted User wrote: »

What's that about keeping the HP temp low, I read that now Air to water pumps can operate up to 60 Deg C ? That's perfectly in line with a oil or gas boiler. They're getting better.

Most HP's will heat hot water to that temp but thats not what they pump into the underfloor or the rads. They will operate at about 30C. HP's havent got better in the last few years. Its "old" technology really.

If you try to get a HP to heat your rads to 60C it will die fast.

HP's are not that suitable for retrofit, IMO. They require underfloor heating or alu rads. Both are costly as retrofit.

Deleted User wrote: »

If solar PV gets a lot cheaper then I'd consider eliminating the potential money pit of a heat pump and dump it in storage heaters, if it's cheap enough and you get paid for excess then who cares if the house isn't so efficient ? this is what her Parents do in Germany and it works a treat, granted they have 14 Kwp on the roof and not the best insulated house but reasonably good, they got a good grant and about 30 C/kwh FIT, so this is why I say that HP's could be a lot costlier in the long run especially if a decent Fit is introduced in Ireland and solar PV drops more and more.

For starters a FiT here at 30c/kWh is not going to happen. EI gave 9c/kWh I think. Unlikely it will be more than that in the future unless someone else has more insights?

I wonder how much more PV will drop in price. If the government introduce a grant or FiT its probably up the price will go. Waiting for these very cheap PV panels could be a long wait... crystal ball required.

Water John

We won't come within an ass's roar of the FIT that the Germans have.

The German FIT has been reduced for new installs since they got theirs installed.

Still, if we got 8-9 C/Kwh that would make a major difference and it means every Kwh produced in excess can be bought back at a later time, the disadvantage is is you have to use this energy during the day because you have to pay peak rates but you will have a better chance to use the energy you generate at peak times also during the day.

Water John

With the amount of commercial solar applied for already, the profile of day rate will change, if a good bit of it is actually contracted.

randombar

Just wondering what the average costs of both A2W and Geo vertical are?

Doorcase

A2W with underfloor for a 2800 sq foot house your looking at 15000-18000. Thats the average. could spend up to 35k

That's a bid mad, take years for a pay back and if it breaks it could costs thousands..... Interesting technology but the cost needs to come down.

Water John

I think that quote is a total. The under floor, manifold controls, Thermostats etc as well as the HP unit.

air

It would be, and those components would have a very long lifetime.
Similar to a conventional oil or gas boiler system where the boiler might have to be replaced but the radiators and pipes could last decades if well maintained.

An oil boiler is substantially cheaper though and far cheaper to repair.

air

Agreed, the point was that the other elements of the heating system still represent the majority of the cost though.

Water John

Yeah Mad Lad, your right. But it doesn't cover the present regs on new house builds.
If you want to go with cheap, head out to the bog and cut your own turf.

Doorcase

I am willing to do that if i got away with it

Water John

Water John wrote: »

Yeah Mad Lad, your right. But it doesn't cover the present regs on new house builds.
If you want to go with cheap, head out to the bog and cut your own turf.

I'm not cheap and I want to remove myself from fossil fuels as much as possible if it's viable to do so.

Water John

I want to get away from fossil fuels too. My house though is not very sealed and unless I put in something like wood gasification, HP with electrical source is out of the question for running cost.
I could use your favoured wind turbine to heat a large insulated tank of water but that would be high capital cost. It is an idea I like if I could hands on a cheap turbine. I have plenty wind.

You can make your own turbine, that's a project I would like to do and who cares if it's not ultra efficient it would be cheap and the energy free, I could power lights use old car batteries etc even dump it into a few electric heaters, immersion etc.

A turbine in Ireland without grant and FIT is uneconomical.

You could also get some kind of electric boiler and install it in line with an oil boiler ? run it off the turbine.

Water John

In winter, heating the house would def be the best use of a wind turbine. The water storage would largely eliminate the intermittincy issue.
A good insulated tank will only loose 1 C in the 24 hours.

Can you get electric boilers ? you could run the house heating then any time the wind blows, use the Oil, Gas, Wood pellets etc when there's no wind. Might actually be an idea for Solar PV also.

air

Of course there are electrical boilers but an oil boiler would be more environmentally friendly.
Forget about Solar PV for heating unless you are planning on a 50kW or bigger array.

https://www.mrcentralheating.co.uk/gold-electric-boiler-4kw#.V_laSSgrKUk

Available in 4, 6, 8, 11 Kw etc, Good cheap way of dumping excess energy and a lot cheaper than a heat pump.

You can also connect two together and have two different sources of power. Connect them in line maybe with oil or gas.

air

What excess energy is this you speak of Mad Lad that's available to dump during the heating season?
My 4kW PV is producing all of 550W at the moment, wouldn't do much resistive heating with that.

randombar

I dont know if I consider 15k a lot more than the standard, it is more but how much more really?

Boiler, 1000 L drum, installation costs, 20 rads, controls etc.

Does it count hot water?

I wonder what the Geo Thermal equivalent cost is?

What would people on this forum do in a new build? For me the UFH plus some kind of pump is kind of future proofing. Harder to upgrade a home with rads and oil boiler if the costs of oil go mad and/or better technologies come out.

Water John

I would def use UFH, but have worked in the ind. Diff type of heat, even from floor to ceiling and no convections. In a well sealed new build also MHRV.
Geo depends on subsoil type. That would be the first thing to look at. Shale rock, sligger unsuitable.
With the world moving on to carbon neutral, electricity from fossil free sources will be the fuel of the future. House thus future proofed using HP.

air

Have to agree with Walter John.
With the level of current building regs it's not a massive stretch to go close to passive standards which means money saved on complicated heating systems.
I'd definitely put in the UFH pipe when pouring the slab anyway, the pipe is cheap to put in and gives you the option of all kinds of low temperature heat sources down the line.

What's all this efficient building regulations ? I still see houses going up with aero board like insulation in the walls.

Water John

Any engineer will not sign off on a building that does not comply. They set very specific min spec insulation for all aspects of a house. Also insist on energyof fossil free source.That really means having solar panels or HP.

A HP is a very very expensive way to meet regulations........

So installing solar PV will meet regulations then ? what's the minimum Kwp ?

Foggy27

Hey all,

I plan to start construction on my own home after the new year, I have been looking at putting in underfloor with air to water system but I've been hearing mixed reviews on the monthly costs, so if people would mind letting me know roughly what it costs them a month I will know if its worth it or not,

Thanks

MicktheMan

Area, orientation, size, design detail, design quality, build specification, build method, build quality, workmanship, personal preference etc etc all need to be answered before anyone could offer any form of a decent answer.
The best heating system is no heating system i.e. build your house with minimal heat loss and you won't need an expensive (to install or run) heating system.