Response times.

A house with underfloor heating will not heat up or cool down quickly – it takes some hours to make a difference. But be aware of this feature… If the sun comes into a room that is already at 20 degrees, the air temperature will shoot up. If the thermostat is in this room, it will switch off – it would be quite possible when the sun goes down for the room to then feel cold, and trying to catch up with underfloor will be too late.

It is essential to have the thermostat where it is not affected by the sun, put simply energy will stay in the slab if the room is hotter than the floor, so the underfloor should be kept running in winter

Windows, solar gain and running costs.

Winter sun (or lack of it) can make a large difference to running costs. Please orientate your house for maximum solar gain in winter. We have had the misfortune to be involved with a small number of badly orientated houses – don’t do it.

Holes in pipes.

For a number of reasons, this does happen. As long as the hole can be found, fixing it is not a major problem. A surprisingly small amount of concrete can be chipped out, and a joiner installed (picture) – these will last as long as the pipe. Frustrating, but nothing to lose sleep over.

Photo Voltaic

Yes, a photo voltaic set will result in lower running cost – we don’t think battery storage is there yet. The economics of PV are quite complex – just bear in mind that even a large PV system will not provide enough energy to heat a house in winter – a 4kW system (produces a maximum of 4kW per hour in summer) will produce no more than 1.5kW in winter – just enough to power a 5.5Kw unit.

Night rate power.

This starts getting complicated, particularly with photo voltaic, battery storage and electric vehicle charging. With night rate, the day rate is higher, do a spreadsheet.

Anti freeze.

In colder areas of New Zealand, using anti freeze is preferable. All units have frost protection, so under certain conditions the circulating pump is switched on, we have never had a freezing problem around Christchurch, but there is a potential issue with prolonged power outages.

Water treatment.

We are aware other installers suggest treating the circulating water (which then leads on to maintenance). All items in our underfloor systems are either plastic, stainless steel or brass. There is nothing to corrode so nothing needs to be added to the water.

Routine maintenance.

In principal there is no routine maintenance to do – hence we don’t recommend or charge for it. If anything goes wrong, give us a call. Probably the worst culprit for this is a sticking circulating pump (after a period of non use), it only takes a couple of screwdrivers and a few minutes to sort out. Incidentally, I can’t think of any problem we’ve had with bronze bodied pumps, as there is no corrosion.

There are a few minor things to do.
Monitor the pressure, it can be anywhere between ½ and 2 bar.
Apply car polish to the outdoor case if you wish.
Check the back radiator of the heat pump isn’t clogged with leaves.