Ashp & sahp combined system

pile-o-stone

Coastalwatch wrote: »

Er, but not exactly Green though, is it?

It's moneysaving though.

Plus the £14k saving (£16k ASHP - £2k gas boiler) would help pay for installing more insulation and higher performing doors and windows. Much greener to permanently reduce heating demand.

martindias

Well the whole idea is to dump the need for gas - yes i know it is cheaper but it is not clean and it's time us oldies played our part in cleaning up the ecological mess we've created in burning fossil fuels. Plus the RIH at the moment almost covers the cost of the purchase and installation of the ASHP plus reduces my utility bills by estimated 50% - with the solar and battery assistance. It does all seem to add up to a win/win.

The house renovation includes extra wall and floor insulation so it won't be a zero emission house but the best it can be. Once i know what it is costing me to run (5 bed house - that's a rather small box room my aunt use to fit in - and two large reception rooms) I'll post it in this thread.

JKenH

martindias wrote: »

Well the whole idea is to dump the need for gas - yes i know it is cheaper but it is not clean and it's time us oldies played our part in cleaning up the ecological mess we've created in burning fossil fuels. Plus the RIH at the moment almost covers the cost of the purchase and installation of the ASHP plus reduces my utility bills by estimated 50% - with the solar and battery assistance. It does all seem to add up to a win/win.

The house renovation includes extra wall and floor insulation so it won't be a zero emission house but the best it can be. Once i know what it is costing me to run (5 bed house - that's a rather small box room my aunt use to fit in - and two large reception rooms) I'll post it in this thread.

You are going into this with your eyes open so if you are comfortable with the costs/return go ahead. We all like a project and you can’t always put a monetary value on the satisfaction you get from seeing something like this through.

ABrass

With heat pumps it's all about the insulation. Roof up to at least 300mm, cavity walls filled and underfloor inhalation is effectively a must. Most of those are required to be eligible for the RHI payments if memory serves.

michaels

Did you look at GSHP? I think you get a higher fit and I understand the heat generation is more reliable when the air temperature gets really cold.

What will you use to heat your hot water above the efficient heat pump temperature?

pile-o-stone

martindias wrote: »

Well the whole idea is to dump the need for gas - yes i know it is cheaper but it is not clean and it's time us oldies played our part in cleaning up the ecological mess we've created in burning fossil fuels. Plus the RIH at the moment almost covers the cost of the purchase and installation of the ASHP plus reduces my utility bills by estimated 50% - with the solar and battery assistance. It does all seem to add up to a win/win.

The house renovation includes extra wall and floor insulation so it won't be a zero emission house but the best it can be. Once i know what it is costing me to run (5 bed house - that's a rather small box room my aunt use to fit in - and two large reception rooms) I'll post it in this thread.

As Ken has said, you are going into this with your eyes open and so good luck with your renovation and move to an all electric home. Like yourself, I own a large, old home (built circa 1750 with 6 beds, 4 shower/bathrooms, 3 reception rooms) and it's hell to heat, even with the A-rated windows, lots of insulation, solar, heat bank, etc. I looked into fitting a heat pump but the running costs would have been ruinously expensive for us. Hopefully it won't be for you, though I really hope you've done your sums and please don't put too much faith in the claims of salespeople.

Good Luck!

martindias

Yep definitely needs a risk taker but got a wood burning stove as a back up....as non polluting type as possible.

pile-o-stone

martindias wrote: »

Yep definitely needs a risk taker but got a wood burning stove as a back up....as non polluting type as possible.

I would make sure that you are absolutely sure that the heatpump will meet your hot water and space heating demands,rather than risk it.

We used to have 2 wood burning stoves, but replaced the one in the first floor living room because it was too messy - lots of ash, soot and sawdust tracked through the house.

We changed it for a gas version. Its looks like a wood stove, but it's much more convenient and far cleaner - both in the house with the mess, but also for the environment due to particulates.



We still have the ground floor wood stove though because it's less distance to the wood store and the stone floor is easier to clean soot from than a carpet.. We replaced a 20 year old massive furnace stove with a new DEFRA approved & EU EcoDesign compliant ACR Larchdale woodburning stove. Not as efficient or as clean as the gas stove, but it's as good as a wood burner gets.



If you can source free wood (i.e. you own woodland or have a tree surgeon in the family) then you're OK. If not, then make sure you understand the cost - it's more expensive than gas because of the transport of the wood to your door. We probably buy £2000 worth of wood a year.

Sorry for going on about the costs, but I just want to make sure you are aware of just how much a large house takes to heat, even if it has been insulated. A Victorian home with high ceilings and large rooms is a big volume to fill with warm air!

Martyn1981

martindias wrote: »

Yep definitely needs a risk taker but got a wood burning stove as a back up....as non polluting type as possible.

This is a weird suggestion, but one that's grown from an idea/chat with my sister who is looking to replace two oil boilers on a large property with an ASHP.

As ~30% of the outside skin is from the original 140yr old property, and is a solid wall, she needs to consider those rooms as the ones most at risk during the extreme end of weather/calculations.

A potential solution I suggested to her is to back up the heating in those rooms, which are actually rooms that will form part of a business side to the property, with small air con units.

This might sound like duplication, which I suppose it is to an extent, but as the RHI does not allow the use of the system for cooling, and those rooms may need cooling (when folk are there) then spending perhaps £2k on a couple of small ASHPs would work well, and provide the top up needed in cold weather if the large air to water system is struggling.

[Luckily, whilst the property is very large, all of the radiators are also large, and double panel, and double finned, plus the piping is 15mm or larger throughout, so the oil system can heat it very fast, suggesting that lower temp air to water heat pumps will manage, but of course run for longer.]

She is also considering a large ground mount solar system, and if possible (and not too expensive) an upgrade to 3phase. Obviously a heat pump and solar combination help each other out a bit on the economics front as the whole becomes greater than the sum of its parts.

pile-o-stone

Martyn1981 wrote: »

Obviously a heat pump and solar combination help each other out a bit on the economics front as the whole becomes greater than the sum of its parts.

Hi Mart, would solar provide heatpumps with much assistance in winter? I don't know what your panels are outputting but mine rarely cover the baseload of the house let alone have access for our immersion heaters (or heat pump if we had one).