What heating system for property?

lancunian

Hi,
I am currently renovating a property in the Scottish Highlands to live in as our permanent home.
It is a detached single stone built 2 bedroom cottage.  It will be double glazed and have loft insulation.  It will also have a bath and separate shower cubicle.  There is no mains gas, (not for over 40 miles).  I am looking for ideas for heating and hot water.
I personally think that heating oil is only going to get more expensive, and I doubt grants are available for oil boilers anymore.  We are looking to live in the cottage for many, many years so should be able to get a return on any system installed.
I am told that there may be interest free loans available for certain boilers, ASHP/GSHP etc.
There will be 8/9 radiators in the cottage and it has a concrete floor.
We would like to look at solar panels in the near future so would an electric combi boiler, despite high KWh prices be an idea?
Any suggestions welcome.

Hexane

My first thoughts are that a large ASHP or GSHP setup could both heat domestic hot water and also heat the radiators (though not to a very high temperature so you may want to take the opportunity to consider radiator bore diameter and surface area when refurbishing) with more efficiency and greater grant opportunities than an electric combi boiler. Solar panels would then defray some of the power consumption of the heat pump (especially in April/May perhaps). How much roof space is there?

lancunian

Hexane said:

My first thoughts are that a large ASHP or GSHP setup could both heat domestic hot water and also heat the radiators (though not to a very high temperature so you may want to take the opportunity to consider radiator bore diameter and surface area when refurbishing) with more efficiency and greater grant opportunities than an electric combi boiler. Solar panels would then defray some of the power consumption of the heat pump (especially in April/May perhaps). How much roof space is there?

Hi,
Yes, good hot water flow is what we are looking for, for baths, and maybe the shower if possible.
There will be quite a lot of central heating pipework as the property is quite long and the distance between the boiler and the furthest radiator will be a at least 40 feet away, I'll get more detailed measurements next time I am there.

Solarchaser

You would get help from energy saving trust and home energy Scotland  could probably visit and give some ideas.
I'd definitely look at solar thermal and possibly underfloor wet heating which is at lower temperatures 

lancunian

Solarchaser said:

You would get help from energy saving trust and home energy Scotland  could probably visit and give some ideas.
I'd definitely look at solar thermal and possibly underfloor wet heating which is at lower temperatures 

Underfloor heating is not feasible as have a concrete floor and the property is over 100 years old.
Looking at standard radiators.

Solarchaser

I thought concrete was good for underfloor heating, but in any case you have ruled it out 👍

EricMears

Solarchaser said:

I thought concrete was good for underfloor heating, but in any case you have ruled it out 👍

Concrete is indeed very good for UFH.  However,  if lancunian has an existing concrete floor,  that would need to be dug up then relaid over the UFH pipes.  Only alternative would be to add a new layer of screed above the (new) UFH pipes fitted above old floor which would reduce ceiling heights by 3 or 4"

lancunian

Yes, want to avoid digging up the floor.😀

tacpot12

UFH without a thick layer of insulation under it doesn't make economic sense. If the floor doesn't have insulation under it, it would be better to add insulation over the existing floor and have radiators downstairs. 

The length of the property shouldn't be too much of an issue. You can lag the CH pipes if the loss from the pipe runs is too high, but the pipes are only losing heat into the property so it's giving you a diffused source of heat into area where there are no radiators, which is not a bad thing. 

Pile_o_stone

Our home was built in the mid 1700s and we have made some improvements and some mistakes along the way while we have been trying to make the house more eco friendly and cheaper to heat and power.

If I were in your position the first thing I would do was to dig up that concrete floor and replace it with an insulated limecrete version with UFH. We did this in the part of the house my parents live in and it is amazing. Concrete and old houses do not mix. The impermeable concrete slab pushes any damp under the house into the walls. Limecrete floors breathe, releasing any water vapour into the room that can then be removed with ventilation. UFH is great for old houses because it is a constant low level heat, plus without radiators on the wall it helps with the positioning of furnishings.

I'd then fit a GSHP if I had the land available for the pipework (and had a garden that was also needing renovation). If not then I'd fit an ASHP. I wouldn;t touch Solar thermal as it's an old technology that is prone to freezing, leaks, stagnation and it stops generating energy when the water tank is full - much better to fit solar PV and an iboost type diverter to your water tank. Once the tank is hot the PV still generates energy that you can use or export for a small profit.

If the outside of the house is rendered stone, then I'd fit external wall insulation. If the outside stone is exposed and is an attractive feature, I'd install internal wall insulation. I'd fit a heat recovery ventilation system and would fit triple glazing at least in your northern facing windows (and possibly east facing ones of they are exposed).

If you're digging GSHP pipe runs, I'd take the opportunity to dig a big hole and fit a rainwater recovery tank so you can flush your toilets, wash your clothes and water the plants with rainwater.

Solarchaser

I confess I was thinking to dig up runs and refill, but POS's points about old concrete makes sense.

I figured solar thermal for 2 reasons, 1 its eligibility for rhi, and 2. Its lower temp generation even in shoulder months would be good (in theory) for running the ufh.