Mon, 25 May 2026 13:17:14 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18982#Comment_18982 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18982#Comment_18982 Mon, 21 Apr 2008 11:58:39 +0100 georgiegirl
http://www.stepwarmfloor.co.uk/index.htm]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18983#Comment_18983 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18983#Comment_18983 Mon, 21 Apr 2008 12:15:05 +0100 Paul in Montreal 1.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18997#Comment_18997 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18997#Comment_18997 Mon, 21 Apr 2008 17:08:09 +0100 joe.e https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18999#Comment_18999 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=18999#Comment_18999 Mon, 21 Apr 2008 17:25:38 +0100 CWatters
http://www.nottenergy.com/energy-costs-comparison2

I don't believe low vs high voltage makes any significant difference to running costs. At the end of the day your house needs a certain amount of power to heat it to compensate for losses through the wall's floor and roof. Power = I x V so if V goes down then I goes up to keep the power the same. Your electricity meter measures power not current so I feel the low vs high voltage issue is a red herring.

Electric may well be 100% efficient (COP = 1) but that's only true if you ignore the 40-60% losses at the power station. My wet UFH system is 100% efficient if I measure it at the right place :-)

If capital cost is no object then an Electric powered GSHP seems to be the thing to go for. The COP of 3 for the heat pump more than compensates for the losses at the powerstation. But do calculate the payback period for all options if that's important to you. Anyone know if gas powered GSHP exist?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19010#Comment_19010 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19010#Comment_19010 Mon, 21 Apr 2008 20:15:24 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19046#Comment_19046 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19046#Comment_19046 Tue, 22 Apr 2008 15:48:30 +0100 Martian This is due to the "fuel factor" weighting of 1.47 in the SAP calculation, which means that when you select electricity as your fuel it is rated as approx 2/3 as efficient as gas. The poor energy assessor was pulling his hair out by the end, from trying to limbo dance under the regulation bar by aggregating the flats into a single figure for the whole block, and even then he only just made it.
My advice is to avoid until we get nuclear power again.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19102#Comment_19102 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19102#Comment_19102 Tue, 22 Apr 2008 21:44:44 +0100 Bluemoon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19106#Comment_19106 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19106#Comment_19106 Tue, 22 Apr 2008 22:00:57 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19130#Comment_19130 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19130#Comment_19130 Wed, 23 Apr 2008 09:07:50 +0100 CWatters
Why is that seen as an advantage? Doesn't it mean that the floor temperature is more or less fixed? In which case the output power is fixed? Fine if that matches what the room requires but what hapens if it doesn't? IHow do you turn it up/down if it self regulates? Just curious as I've no direct experience with electric UFH.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19137#Comment_19137 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19137#Comment_19137 Wed, 23 Apr 2008 09:56:07 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19138#Comment_19138 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19138#Comment_19138 Wed, 23 Apr 2008 09:59:52 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19141#Comment_19141 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19141#Comment_19141 Wed, 23 Apr 2008 10:06:10 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19147#Comment_19147 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19147#Comment_19147 Wed, 23 Apr 2008 10:28:43 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19154#Comment_19154 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19154#Comment_19154 Wed, 23 Apr 2008 10:50:51 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19175#Comment_19175 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19175#Comment_19175 Wed, 23 Apr 2008 12:50:51 +0100 Paul in Montreal
As for self regulating, that's just marketing hype. Any electric underfloor heating system is self regulating in that it can't provide more heat than being run continuously - the temperature will come into an equilibrium (i.e. self limit) based on the heat loss. All electric systems can be fitted with a thermostat to maintain a certain temperature and the duty cycle can be surprisingly low. I have a very small (3 feet by 3 feet) electric UFH system in my bathroom - "full on" power is only 180W but with the programmable thermostat and timer, it's only on for a small percentage of the day (1st thing at morning, late evening) and once it's at temperature, the duty cycle is very low. The area being served is so small that a wet system makes no sense. For a primary source of heat covering the entire ground floor, say, a wet system is by far the best way to go. A properly zoned wet system will also be thermostatically controlled - we have a system in the new house using Wirsbo equipment which has temperature sensors embedded in the slab in each zone controlling motorized valves.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19178#Comment_19178 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19178#Comment_19178 Wed, 23 Apr 2008 12:59:43 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19181#Comment_19181 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19181#Comment_19181 Wed, 23 Apr 2008 13:15:20 +0100 Bluemoon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19188#Comment_19188 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19188#Comment_19188 Wed, 23 Apr 2008 15:00:07 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19190#Comment_19190 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19190#Comment_19190 Wed, 23 Apr 2008 15:17:42 +0100 Paul in Montreal Posted By: tonyI dont think that resistance heating is ever the best option nor will it ever be.

Depends on the area - for a small area like a bathroom, it probably has the lowest life cycle cost. The equipment is simple and cheap to install and consumes very little power - even if a wet system is more efficient (using whatever measure you want) because it is more complex the saving may never be realized. The small resistance setup I have in my bathroom uses such a small amount of power that I can't detect it in my religious meter reading (I take readings at least once a week and have done over the past three years to correlate climatic conditions with energy usage). I agree with you, though, for the primary heating source for a large area.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19256#Comment_19256 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19256#Comment_19256 Thu, 24 Apr 2008 14:12:39 +0100 CWatters https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19264#Comment_19264 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19264#Comment_19264 Thu, 24 Apr 2008 17:52:08 +0100 georgiegirl
'STEP Warmfloor™ only uses on average 50 Watts/m² whereas Water underfloor heating products use between 70 Watts/m² and 85 Watts/m² and Electric Cable products can use between 150 Watts/m² and 300 Watts/m². We therefore use less energy to achieve the British and European Standard for floor temperatures of 28ºC.']]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19274#Comment_19274 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19274#Comment_19274 Thu, 24 Apr 2008 19:22:16 +0100 Paul in Montreal
Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19280#Comment_19280 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19280#Comment_19280 Thu, 24 Apr 2008 20:43:09 +0100 Pete1951 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19390#Comment_19390 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19390#Comment_19390 Fri, 25 Apr 2008 22:05:35 +0100 CWatters
Basically this means that if the air in your house is at a constant temperature the energy coming in and going out will be equal. In other words the power supplied by your heating will exactly match that being lost through the walls, floor and windows etc.

In _theory_ this means that it doesnt matter what heating system you use...if the house is leaking 10KW it needs 10KW of heating or it will get colder.

In practice there are some differences, for example UFH is claimed to heat the bit of the room that people are in (the bottom 6 foot!) allowing the average air temperature overall to be cooler for the same level of comfort. I'm not particularly convinced on that one.

If the floor is well insulated very little will escape downwards and most will go into the room. So I'm with Paul on this. The source of the heat should make very little difference.

> It is not recommended to have a high temperature wet UFH system and you are relying on the water
> temperature thermostat to control that.

In my wet system I reckon three things would probably have to fail.

The stat on the thermal store.
The mixer on the manifold.
The room stat.

Perhaps you could obtain government statistics on the number of people a year who burn their feet due to faulty UFH?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19392#Comment_19392 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19392#Comment_19392 Fri, 25 Apr 2008 22:19:12 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19397#Comment_19397 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1609&Focus=19397#Comment_19397 Fri, 25 Apr 2008 22:39:59 +0100 Pete1951