Underground Heating

Culchie

Hi,

First Time Poster on this forum (never thought I'd see the day:o )

Anyways ... We will commence building our own house quite soon, and interested in the underground heating system (energy is derived from the soil).

I believe " costs are about €20k to install, but greener solution, that should pay for itself within 5-7 years, with energy prices the way they are now"


I heard the above view on a radio interview .... any boardsters have a view?

karltimber

have a rummage through Soc- green issues
they have a lot of info over there for you.

look here also - just might need to go back a few days/weeks

Viking House

If you spend an extra €10k on insulation, then a €10k Geothermal unit should be sufficient and a lot cheaper to run.

Qwerty?

The more insulation you use the less the heating costs will be with Geothermal - so insulate, insulate, insulate

True about 10k will get the pump, but depending on the house size another 10k will be the price of the UFH pipes and labour. (approx €35-40 per metre.) plus the Cylinder and geo loop.

You building in Mayo?

yop

As the lads said, insultion is seriously important.

One thing I have begun to learn is the benefits of passive heating, we really did not use the amount of heat which we could have got from the sun by loading the house with windows or veluxs but lesson learned!!

As the lads said you are talking anything from 8-10k for a brine, 10-12k for a DX geothermal system.
UFH for ours (2100sq ft)was 4500 put in by ourselves or cheapest quote for supply and install was 8k.

There is an interesting house going up outside Westport on the Louisburgh road which is similar to a Kingspan TEK house, they seem to be doing everything, kit, windows, slating, doors. Serious loooking panels going into it.

Culchie

Qwerty? wrote:

The more insulation you use the less the heating costs will be with Geothermal - so insulate, insulate, insulate

True about 10k will get the pump, but depending on the house size another 10k will be the price of the UFH pipes and labour. (approx €35-40 per metre.) plus the Cylinder and geo loop.

You building in Mayo?

Outskirts of Sligo, 4 bed bungalow.

Thanks for the replies, better get this right straight from the start.

I'm off to the Soc - Green forum now, thanks for that Karltimber.

Peace Man

smadger

Hey guys,

How much extra insulation did you guys add? My builder put 50mm of Xtratherm in the cavity (its a block house), but says if I want more he can put insulation backed plasterboard on the inside.

We'll be doing UFH + heat pump in a 2900 sq ft house.

What's a reasonable amount of insulation to add/ Am I mistaken that there are various thinknesses of the plasterboard with insulation?

Cheers

RedLady

Hi,

We are building in TFH with standard kit from century but we did opt for the r2000 airtight frame. The u value of the walls is at the standard .27 value. If I want to upgrade this down to .23 with kingspan structured panels it would cost an extra €5000 - would it be worth this? I am guessing not as we have put in a lot of windows on the south side of the house where most of the living areas are.

Any thoughts/feedback welcome.

yop

On the insulation side of things.
External walls 150mm rockwoo.
Internal walls 100mm rockwool.
Under final floor and UFH 100mm of Xtratherm.
Ceiling space between ground and first floor 100mm fibreglass.
Roof space on slope of dormer 100mm kingspan.
Ceiling space above firstfloor in the attic 100mm fibreglass

RedLady

Hi Yop,

I saw that house in westport over the Easter period.

Are you happy with the amount if insulation you put in. Do you know what U value your walls are with that amount of insulation?

Regards

smadger

Thanks Yop! That's helpful.

yop

RedLady - Not a clue to be honest. Based on the complaints from the tradesmen of the heat (which is great!!) I presume it is low.!

Qwerty?

smadger wrote:

Hey guys,

How much extra insulation did you guys add? My builder put 50mm of Xtratherm in the cavity (its a block house), but says if I want more he can put insulation backed plasterboard on the inside.

In hind sight I think I would have gone with insulating the inside of the external walls with insulation backed plasterboard. Maybe next time...


My insulation was as follows:-

External walls of 105mm platinum aeroboard (bad choice)
Under ground floor 100mm of Xtratherm.
first floor 25mm xtratherm
sloping Roofs 100mm xtratherm and 35mm xtratherm insulation backed plasterboard
attic 300mm fibreglass

beolight

In hind sight I think I would have gone with insulating the inside of the external walls with insulation backed plasterboard. Maybe next time..

would it be foolish to dryline the walls and add internal insulation in this situation?

anon1

You get diminishing returns after 50mm of urethane type insulation.

Viking House

Insulation is not only about U-value. It is also about density and breathability and about how long it takes heat to make its way through it.

With no heating on, low density insulation, gives a hot house by day in the summer and a cold house at night in the winter.

With no heating on, high density insulation gives an even temperature through the day and night winter and summer.
This is called Decrement Delay (U-value multiplied by time), the ideal Decrement Delay for an insulation material is 12 hours or more.
Denser insulation buffers the daily variation in temperature.

Low density petrochemical insulations like Polysterene and Polyeurethene (Kingspan and Xtratherm) give what is commonly known in the insulation business as "The Caravan effect". On a hot summers day the inside of your caravan is like an oven after an hours sunshine.

The opposite to this effect you can see in your own house with your dishwasher. The stainless steel drum is lined externally with Paroc granitewool insulation, most people turn on their dishwasher at night and in the morning when they open the door they get a waft of heat from the dishwasher. The dishwasher has been stopped for over 6-8 hours and it still maintains its heat.

It is not allowed anymore to use Polysterene and polyeurethene inside your house in Scandinavia and Central europe because of offgassing.
Why line the inside of your house with plastic. Its like putting your head inside a plastic bag.

Kingspan in my opinion is a dirty industry because for over 10 years they used CFC gasses to produce Kingspan in Ireland before they were forced to stop by the EPA. They knew they were ruining the Ozone layer but didn't care.

We use Paroc and Softboard because they are the best for Decrement Delay.
The partial fill cavity wall insulation in reality only gives 50% of what it is designed to do because of Thermal Looping, so if you build a wall designed to give you a U-value of 0.27 you get a U-value of 0.54 in reality.
When you dryline you only actually insulate 90% of the wall because of cold bridging.
The best place to put insulation is on the outside of your walls.

In our Passive Timber-frame houses we use 250mm Paroc in the walls and 300mm in the roof.
In our Passive block houses we use 150mm of Paroc on the outside of Poroton blocks.