[Closed] How should I heat our next home

Insulate enough and you really won't need much heating. Passive is hard to achieve when renovating but possible, get close and just turning on the TV and hi-fi sees the temperature ticking upwards.

Some questions first:

Are you prepared to spend time lighting, fueling and cleaning a wood burning stove? In our case we only light in the evening and rarely (if ever in a mild Winter) see less than 18°C before lighting the next evening.

Do you have a south facing roof with no shade?

Are you going to spend at least 15 years in the property?

Friends have a ground-sourced heat pump that feeds under-floor heating and very nice it is too with an efficiency of 4.5 - 5 (each time I quote this someone disses it). 16 000e means you don't want to install it if you might move on. A German friend has an air-air heat pump which is a lot less efficient but if you have a huge roof then the double benefit of feed-in tarifs and using your own PV production might make it viable.

You need Stoner or Bear to advise on pellet boilers.

I've got a solar water heater that works great and will pay for itself in 11 years but I'm at 43°N. You need Stoner to report on efficiency at 52°N.

You are an ideal candidate for GSHP because: you can design an optimal delivery system (under floor being a common choice) and you have plenty of ground to install an horizontal array to collect heat from the ground. (This is the second cheapest way to collect heat).

I won't diss Edukators efficiency number and the RHI seems very generous, compared to when I was last looking at commercial GSHP.

You need to find an installer with lots of experience though as the design and controls are important for an efficient system.

Make sure every external door has a porch (with door) and/or vestibule.

Also, if possible, once inside you don't need to use the hall(s) to get between the rooms.

And LPG? Cheapskate try oil 😉

We have an outside room, which was cold... until we got it dry-lined with slabs of Kingspan topped with plasterboard backed with polystyrene foam. It has completely transformed the room, which is now warm, cosy and quiet. When we next move house we won't hesitate to dry line every outside wall throughout the entire house before moving in, so spectacular has been the effect on our cold room.

You no doubt divided (reduced) the heat loss through the wall by six, Globalti.

Don't forget to include adequate ventilation when you insulate so heavily.

Out of interest is there any mileage in fitting exterior insulation to cavity walls? We have cavity wall insulation, but really don't have much confidence that it's been done properly (previous owner installed), and the house seems to lose heat quickly.

You are an ideal candidate for GSHP because: you can design an optimal delivery system (under floor being a common choice) and you have plenty of ground to install an horizontal array to collect heat from the ground. (This is the second cheapest way to collect heat).

A great deal of cats and dogs. 50 of each should do. Will be nice and toasty*

Side effects may include noise, smell and floor gifts.

If you have many thousands to spend on GSHP, don't waste it on a GSHP, spend it on more insulation, and a few hundred quid's worth of electric radiators and fan heaters.

We have a ground source system. Where we live now there is no gas and we weren't getting oil or tanked gas as it's silly money. We had to dig the garden up anyway (it was an old B and B and garden was mainy a car park). We have underfloor heating downstairs, and rads upstairs (it was just too much work to get UFH into the bedrooms) and obviously all our hot water running off it.

We used NuHeat who were great and a NIBE pump and a(MASSIVE) tank. Had a few issues with the heat pump, but the system is brilliant. When we moved in we had storage heaters and they were rubbish!

I love UFH (under wooden oak engineered floors) so much nicer than rads. We calculated the cost at about 60%-70% of gas (if we could get it). It'll also take a solar feed into the tank.

A lot of people are very sniffy about GSH, but if you do it right, it can be a very efficient way to heat your home. Up front cost was pretty steep but we did get a grant as well. Email is in profile if you wnat to know more.

Somewhere I have pics of us putting it in (inside and outside) but all I can find is an 'after' photo showing part of the garden!

[url= https://farm4.staticflickr.com/3359/3476699311_49f508fed8.jp g" target="_blank">https://farm4.staticflickr.com/3359/3476699311_49f508fed8.jp g"/> [/img][/url][url= https://flic.kr/p/6idZzz ]The Manhatten Experiment[/url] by [url= https://www.flickr.com/people/60876362@N00/ ]Alex Leigh[/url], on Flickr

If you get down to 44W/m2/year (passive) then a 100m2 house only requires 4400kWh/year to heat which costs around £500 of electricity and one 1500w electric radiator. We use the wood burner but leave the radiator set at 5°C if we go away during a freeze. It hasn't come on since we started using it that way but does mean madame doesn't have to light the wood burner if I'm not around. Our solar feed in contract says we have to consume at least half what we produce so we have to waste electricity some time.

The RHI makes the upfront cost much more manageable.

Thanks for the advise.

We will have a couple of wood burners anyway, I have no problem cleaning them out (had a multiple fuel system at my parents when I was a kid). But the wife and more importantly my lads Carer wouldn't be so happy with doing it.

The house (at the moment) is 2 cottages side by side, the roofs are mostly east to west, but only of them has a small south facing one (about 5 or 6m2 if I had to guess).

Will definay staying for a lot longer than 15 years.

I'm pretty sure there wasn't cavities when they were built, but we are removing most of the back one so that will be up to modern spec.

Point about doubting up on doors taken.

I think I'm going to push pretty hard for GSHP, as advised I just need to find a good installer.

Does anyone know if you can get 2 RHI grants, one for GSHP and one for solar? Will I get 2 FiT's?

Alex, I'll drop you an Email later, thanks for the offer.

Just something to bear in mind with the under floor heating, we've done a few jobs for schools with children of varying mental/physical abilities whereby the pupils spend a lot of time on the floor. The upshot of this was, there would often be a covering of mats over most floor areas which would effectively insulate from any underfloor heating (some of the childrens conditions could also be worsened or episodes brought on by overheating). Instead we went for space heating via blown warm air, with a load of photovoltaic panels and air source heat pumps (as well as the usual insulate insulate insulate...). Just something to consider if you'd prefer carpets or something for similar reasons.

Long term effectiveness of GSHPs can be a bit iffy for domestic installations as they are normally relatively shallow and closed loop, so in the long term there have been instances of ground freezing and reductions in efficiency (more so with shallow coils).

How about an air source heat pump?
Installation costs are significantly lower that ground source and some of the figures I have seen have suggested decent efficiency.
Mention was made on the radio today on mini CHP plants too.

I can't offer much more detail, just putting these ideas in as part of the thought process.

Friends new build farmhouse uses airsource heat pump and a massive water tank. Saved the groundworks of ground source as for them this would have meant digging up the farm yard.
Got pellet boilers in places at work, wouldn't bother, not far behind oil in costs.

The small south-facing roof would be enough for solar thermal. The next questions are: are you going to insulate the roof space and could you get at least a 200l tank higher than one panel on the roof. If so you could have a thermo-syphon pre-heat arrangemnt with no pumps or controls that feeds whatever other hot water tank you decide on. My German friends with solar thermal have problems either with pumps and control systems, or with the system not circulating much of the year because they only have one tank which is warmer than the water in the panel. Under-sizing panel area keeps costs down and avoids boiling if you go away for a sunny weekend.

Do all the more more cost effective stuff such as insulating, wood burner and some sort of heat pump first but have the pipes put in when you have all the other work done (if you have wood burners as the main heat source I'd go air-air as the extra cost of ground-air will probably take longer than the life of the unit to recover). I did intend to fit an air-air unit myself but the results of insulating were so good it became unnecessary.

Honey badger, you make a good point (off topic, honeybadgers are easily my favourite animal).... Tom has lots of "problems" and spends a great deal of time on the floor as it gets him out of his chairs and a bit of freedom. I was looking into sexy matts to make him more comfortable, I need to bear in mind they may prevent the very thing I'm trying to achive.

One of the issues with the house is there is no roof space. We are looking at kingspan to line the space inside.

We've got an air source heat pump. Clean, cheaper than GSHP, ideal is with underfloor - runs for longer at lower temp. If I could, I'd add a solar preheating system, heating the water before it goes into the hot water tank.
We have PV panels.
We figured elec prices won't increase as much as other sources.
Wife's an architect - you're welcome to visit - we're near sunny Keswick

We figured elec prices won't increase as much as other sources.

Don't look at DECC projections then, they indicate the opposite - one major factor being the subsidies are loaded into electricity prices.

Solar PV panels aren't going to get more expensive relative to income so you can produce your own electricity for heating if grid power gets too expensive.

Panels are now so cheap you can produce yourself for under .15e/kWh according to the Fraunhofer Institute. In Germany that's less than grid power already. Producing for heating in Winter with the sun lower in the sky would require installing the panels at a steeper angle and you'd need a lot, more than would fit on the roof of a house so they'd have to be free standing in the garden. I'd need about 20kWh a day to replace the three-hour evening wood burn needed in cold periods (which are generally sunny where we live). That would require about 40 panels based on current December production.

Firstly 3500 quid 😯
Secondly 3500 quid 😯

Ground source sounds good for you. Air source does not often stack up when compared to gas, but if you are off grid it may work. The problem you will have with any heat pump is that you can't heat hot water with it, at least, you get very poor efficiencies over about 45 degrees.

I would argue that you may not need hw over 45C but the problem is that this temperature will grow legionella so the useable water cannot be stored at this temperature. However, you could use a large cylinder as a thermal store/buffer vessel for the GSHP and run cold water through a coil/heat exchanger in the tank to effect an instantaneous water heater. Connect the tank to a solar thermal system and you probably have a decent integrated hw and heating system. There ids a company that makes suitable tanks but I forget the name, will try to find out

If your looking at such a big job, with plans to live with if for such a long time, get some professional help. Not a builder, or bloke from the pub, but an architect who really knows what they are doing with regard to retrofitting a building (of your type) for the things you want to achieve. It will cost you money, but payback worth it.

The thread has touched upon insulation, but the majority of the comments are about heating. In my view this is wrong. If you have a wedge of cash (sounds like you do), spend it on making the property thermally efficient, I mean really thermally efficient. Once you have done that, heating costs will either be so minimal as to not worry about, or non-existent.

If you do go down the route of GSHP, research your contractor. Many of the stories that I hear, where GSHP (etc) is failing, is because its been installed badly. As you might imagine, its really not something you want to be re-insalling. I think this is a particular problem in the UK, where its uncommon, and very little residential experience exists.

Like I said at the beginning, hire an expert. I am not one.

My own experience is that architects see energy saving as a headache they have to get around to get their ideas approved. On the other hand I was offered excellent advice by a French government paid energy adviser in 2008 which formed the basis of priorities and work done.

Architects like:

Space (which needs heating), big volumes with high ceilings (heat rises and it's all extra volume to heat and surface area to lose heat), interesting shapes (which have more surface area than a cube), open spaces (which mean you can't get cosy in one room and leave the rest of the place at a lower temperature),glass (which is OK in moderation if it's double glazing south facing or triple glazed E/W facing and gets sun in Winter but not Summer).

I visited an architect-designed solar house in Freiburg and while it was bristling with "eco" features the place must be an energy disaster on overcast days when it's -15°C which is common in the Black Forest.

While you're doing all the work you can at least DIY fit a solar tube array on that roof and use it to pre-heat the water entering the house by running it through a coil in a second-hand cylinder plumbed in tandem with the main house cylinder, assuming you're not going combi. Cheap and easy to do.

Just had a run followed by a shower. October 17 and water from the solar tank is still hot enough. I'm on my own this week though, if Madame and junior were here too I'd have to run the water through the normal immersion heater tank to get a hot shower.

get close and just turning on the TV and hi-fi sees the temperature ticking upwards.

For reference, this happens in our living room in winter, in a bog standard new build house. In fact we have to open the door to let colder air in 🙂

Very tempted to fit solar HW to our very large south facing windowless wall...