In Slab heating?

[muzza]

Anyone installed or has comments on In Slab Heating?

We are building a new home and are having the living/dining/family/ensuite with ground/polished concrete, hence the need for slab heating.

So far have found out;
1/Electricity seems cheaper to install but expensive to run.
2/Gas boiler more expensive to set up bit cheaper to run (but we're not on gas line so bottles will be expensive)
3/Heatpump (to heat water in pipes in slab) very expensive to set but very cheap to run.
4/Our builder has diesel boiler but didn't recommend it

Any comments would be appreciated

[SuperDad]

What are the respective set-up and running costs for each?

How much heat will each option provide?

Also, can the electric option be run on ripple control? (11c/kW vs 19c/kW for anytime power).

Paul.

[muzza]

electric can be on off peak supply.
set up costs so far around 6-8k for electric ($300-$400/ month run cost, and someone said $700/month) 15-17k heat pump ($100-150/month run cost), gas somewhere in between (& $200-300/month and someone said could be up to 600 plus on bottles), I have just got verbals and we now have foundation plan to give out for quotes.
and of course each one we phone has there own biased opinien on which is best.
contacted 'consumer' and they have done tests on heat pumps e.t.c. but haven't done on inslab heating.
can't seem to get an unbiased point of view, hence thought would try here to see if anyone has had any experiences perhaps with different systems

[Heg]

We have electric under tile heating in our bathroom and it sucks. It takes the chill off the floor but it never really gets that warm. We're Poms, so are used to gas central heating (radiators) which are lovely and toasty. Gas would be my pick simply because of the cost of elex.

[deliveryman]

.....go solar

.....have friends who put in a solar panel on the roof to heat their slab, and another for their hot water and a third to keep their pool warm. maybe better in the north but sunlight is my favourite price - free.....

[NESW]

Check out http://www.floorstore.org/ as an option, I haven't personally used it yet, but its been recommended to me several times elsewhere.

[dksnz]

Another option....

Came across this the other day at the AK Trade Bldg Show - I am after the same thing [polished slab] on my next house - build the slab on cupolex domes [www.cupolex.co.nz] & in the airspace under the domes have hot air blown/drawn into it {not sure if they have info up yet but worth enquiring]. I have undertile heating currently but wouldn't want this over a whole house - gotta be a better way & I have heard the waterpipes are expensive, but this hot air way has some merits...

[SuperDad]

My wife and I put tiles throughout the living and wet areas of our first home. We didn't have undertile heating.

I found that if one kept the air temperature warm enough, the floor was not so cold.

I would personally spend $15-20K on putting heatpumps throughout the house, to heat the air.

If this was not enough, I would buy a good pair of slippers.

Paul.

[NESW]

Something to keep an open eye on....

One of the problems I have heard in the NZ underfloor heating market is the placement of the underfloor heating pipework can be too far apart.

I have been told, but have not yet seen it for myself, that the pipework should be no further than 200mm apart.

I assume that those providing a cheaper quote might be cutting corners in this manner, thus reducing the overall cost of the product, to gain the business, whilst making the final result fairly useless.

Anyhow, just something to keep an eye on. We are certainly going down that track with our future NZ home... but are looking at installing a European "boiler" using wood pellets to produce our heating requirements. All the rage o/s.

[muzza]

thanks for your comments guys

[MikeO]

We have electric in-slab underfloor heating in our house (on the night rate). I don't know much about it as we didn't build the house but we find it really good. Keeps a fairly large house up around the 21 degree mark for maybe $150 per month on top of the 'usual' power bill (not bad for christchurch). The first power bill after you turn it on is a bit more as it gets up to temperature but overall fairly economical.
I'd definitely consider putting it in if I built a place but obviously solar or heatpump driven could be better again

[muzza]

thanks Mike, I would be happy with that bill, the opposition say it would be 3 x that much but the electric guy doesn't. he did admit that the start up when the concrete is 'green' will cost a bit to dry and heat but if you insulate well (polestyrene under slab & good wall/ceiling insulation), as you say once heated is quite efficient on off peak supply.
picked up a comment on solar panels ,that they start to deteriate after 7 - 10 years, and with the higher set up cost tis is when they are meant to start paying for them selves

[MikeO]

Yeah we are happy with it. Our house was about 6 or seven years old when we bought it so the green concrete piece wouldn't have affected us.
Definitely not $450 a month on night rate. I don't think it has ever been that high even when we first switched it on.

[KapitiInvestor]

Slab heating

Do not install slab heating unless you can install it on adequate insulation, both under the slab and up the walls. Otherwise the losses are too high, more than the pros and cons of the different heating systems.

Install it at 200mm centres. Larger separation can cause heat stripes, which can damage flooring materials through differential movement. Again for this reason install enough pipework to do the entire floor, not just a zone in the middle.

Each room should have its own manifold valve, and electric thermostat. You dont need a lot of heat in the floor to heat a room, and to much can be unbareable.

Wet systems can have a mixing valve to ensure the water temperature stays consistent and low, which stops you overheating the floor and cracking tiles. Electric has only one heat and so can be unpleasant on the ancles when at full pelt.

Steve