Geothermal v Solar

[Shay O Toole]

I am building a house at present(2700sq ft) The Architect is recommending Goethermal but I have heard horror stories with regards to energy bills.Can someone give me an independent asessment of my options please.

 

[quentingargan]

I am building a house at present(2700sq ft) The Architect is recommending Goethermal but I have heard horror stories with regards to energy bills.Can someone give me an independent asessment of my options please.

It doesn't have to be either/or. I have seen lots of houses use geothermal to heat the house in winter, and solar for the hot water in summer. A well installed geothermal system has a lower cost per KwHr than oil or gas, but probably not as low as pellets. Though pellet storage has caused some problems in the past too.

Geothermal can work OK if the building envelope is very well insulated, but it tends to run underfloor, and keeps the house warm day and night, rather than heating on demand from oil/gas/pellets and radiators. If it can be used on off-peak night time electricity only, that helps, but usually there is a top-up needed in afternoon, which is when electricity (wholesale) is at its most expensive. Smart metering means that the wholesale price of electricity will be passed on to consumers at some time in the future, and at that point this top-up element will become very pricey IMHO.

 

[dgeers]

Hi
We opted for a Air-source heat pump instead of a geothermal one. If you are still in planning plan to insulate the living daylights out of the house, we opted for triple glazing overall , insulated plasterboard on inside wall and EPS insulation in the cavity, 200mm underfloor insulation on the ground floor and heatrecovery ventilation. We took the view we can change the finish of the house but you are less able to change windows and insulation etc

So far the only "proof" of its success is that when we had the "hot" summer the painters commented on the house being very comfortable to work in.. ;o} , at the moment with the mild weather we don't have to do a lot to get the house on temperature ( it hovers around 18 - 19C).
To remove the "chill" we fire up the stove and that takes the downstairs to 20C within 2 hrs. electricity wise the heatpump has kicked in for about 24 hours in total over a month the electricity bill ( first one ) was under the 200 euro that is heating / hotwater/ cooking ( the rest of the house is LED and where possible AAA appliances)

We have moved 4 times in the last 4 years and have been living in various houses in variable degrees of comfort , my kids love the fact they can walk bare feet on the tile floor even without the heating on.
We'll see what the winter will bring, I'm hopeful that the house will perform and the heating requirement will stay within expectation. Experiences might vary .. mine might too if its gets "really" cold.. but for now all good..