Wood burners - and open fires

[Cockney Sparrow]

The next door house was demolished and replace by two semi-detached houses. The developer/builder said that apart from high thermal insulation the house had to have a principal energy saving feature and he chose air heat source.

Thinking about it, we never hear the unit (looks like an air conditioning unit - its about 5 metres down the back garden with a fence obsuring it. We've never heard it - but then in high summer with windows open its not likely to be working.

The unit feeds solid floors with underfloor heating. Whenever I have been in their house (occasional child minding for short periods) its been warmer than ours - shirtsleeves in winter (and I have maximised insulation in a 1960 house). The only problem was in finding a firm which would be willing to turn up and deal with a problem on the first floor (which wasn't resolved for over a year - by using an Toshiba authorised firm.

IIRC what's needed is a large surface area to emit the heat constantly, as water temperatures in a wet system are markedly lower than with a boiler, so radiators wouldn't deliver enough heat without being overlarge and intrusive in the room plan and use.

We have a family room with underfloor heating, run off a mostly conventional gas boiler/radiator system and we use it from Late November to February as the constant heat makes it a good place for Mrs CS to work or relax. Again, maintenance was a problem and I did it myself on the occasion it was needed. To keep gunk out of the water in the system (particularly the underfloor pipes) I use anti corrosion additives (and have a test system to keep it effective) and also had installed one of the devices which captures ferrous particles from the flow by using magnets.

[ardcarp]

I fear that underfloor heating is not good for pianos, especially uprights which sit on the...er....floor. My sister lives in Norway and her lovely house near Oslo has underfloor heating, triple glazing ...and a wrecked upright Blüthner! Such a shame. I think in a new-build, one can have individual controls over separate rooms and even (to suit your piano or other furniture) separate areas within a room.

Maybe in Norway one feels the need for a very hot house. We tend to visit every other Christmas (not this one, sadly) but find the indoor atmosphere far too hot and dry. Furthermore the huge contrast between being outside. swaddled up against the snow and ice. and coming indoors is surely more than the human body was ever intended to endure? Electric underfloor heating was fitted very widely in Norway in the past, as hydro-electric power was initially very cheap. I think that has changed, since prices of most things in Norway are eye-watering. However, I understand electric vehicles are now very widespread in Norway and don't have to pay the city-charge when driving in Oslo.

[Dave2002]

The next door house was demolished and replace by two semi-detached houses. The developer/builder said that apart from high thermal insulation the house had to have a principal energy saving feature and he chose air heat source.

It does make more sense to prioritise heat pumps over other environmental changes, such as electric cars. Even though transport is a major factor in the UK re energy consumption and greenhouse gas emissions, it's still quite small compared with domestic heating.

It really should be a priority - as also encouraging the use of much more effective insulation .... but then .......

[oddoneout]

It does make more sense to prioritise heat pumps over other environmental changes, such as electric cars. Even though transport is a major factor in the UK re energy consumption and greenhouse gas emissions, it's still quite small compared with domestic heating.

It really should be a priority - as also encouraging the use of much more effective insulation .... but then .......

Given the ban on installing gas boilers in new builds there is likely to be a rash of AHPs being installed. Unfortunately they will be put in following the usual developer practice of ignoring anything approaching best practice, proper(ie not UK)minimum insulation standards etc - or even making sure the 'installers' have read and understood the instructions (the concept of employing experienced installers fails due to lack of such people, let alone the dislike of using skilled tradesmen)and the occupiers will find themselves with a useless or badly functioning bit of kit for which they will have had to pay a premium - because the developers aren't going to fund them. It's going to be sharp practice high profits heaven.
My comment about fan noise is to do with my problems with whines, hums and similar sounds, not a generic 'AHPs are noisy'.

[Anastasius]

.....neither are condensing boilers (although I have read that such boilers now do work efficiently in normal domestic settings but I remain doubtful). ....

You're right although it's not related to the particular setting. The majority of condensing boilers are rub with a much too high heat out which makes them operate outside their condensing mode.

Perversely Dave 2002's underfloor system is probably better suited to a proper efficient temperature setting for a condensing boiler.

[Anastasius]

Our oil burner service man installed ground source heating in his new house 4 years ago and eventually after much heartache got it working, but he tells me it is only adequate, takes ages to respond to temperature changes and was extremely expensive to install. Perhaps systems have improved in recent years but its difficult to see how how either air or ground source can ever respond quickly enough to be as flexible as gas or oil until engineering ingenuity comes up with a solution.

It's a different philosophy and only viable IMO in a modern well-insulated house with underfloor heating. Certainly not radiators in a leaky old house.

[Anastasius]

,,,
My comment about fan noise is to do with my problems with whines, hums and similar sounds, not a generic 'AHPs are noisy'.

Maybe a PROM world premiere ?

[oddoneout]

You're right although it's not related to the particular setting. The majority of condensing boilers are rub with a much too high heat out which makes them operate outside their condensing mode.

Perversely Dave 2002's underfloor system is probably better suited to a proper efficient temperature setting for a condensing boiler.

Indeed, and given the small size of so many houses in this country the chances of condensing boilers ever having a long enough pipe run to lower the return temperature enough in an ordinary radiator CH system are low to non-existent, even taking into account rubbish insulation levels.
Some years ago there was an open house type scheme here over about 4 years run in conjunction with Heritage Open Days which gave the opportunity to see various types of 'green' and alternative systems - heating, power generation, water management etc - in real homes, and to talk to the owners. Although obviously things have moved on for some of the technologies the basics still hold good and hearing about the pros and cons from real people using them rather than salespeople is invaluable - and also really interesting in many cases since the people involved were by definition slightly out of the ordinary.

[gradus]

It's a different philosophy and only viable IMO in a modern well-insulated house with underfloor heating. Certainly not radiators in a leaky old house.

It was a new build on a big site with loads of space for the GS pipe runs. I got the impression that the installation tried to follow the rules but somehow didn't deliver the intended results, perhaps too early an adopter with no expertise behind the installation?

[Dave2002]

You're right although it's not related to the particular setting. The majority of condensing boilers are run with a much too high heat out which makes them operate outside their condensing mode.

Perversely Dave 2002's underfloor system is probably better suited to a proper efficient temperature setting for a condensing boiler.

Perhaps not ....

[oddoneout]

Earlier mention of ground freezing reminded me of Canvey Island where problems were encountered with the liquid natural gas storage tanks causing permafrost ground movement. The subject came up while I was a student when we were looking at effects of glaciation and caused us some amusement, and not a little concern for those living in the locality.
The problem of extracting heat possibly causing problems for the 'heat source' is something I wonder about when I see proposals to use a static(such as a lake) rather than moving(river) water source. Mind you I suppose such a scheme could be useful for lowering the temperature around power plants whose cooling water demands cause unacceptable temperature rises? Again this was something that came up as a student when it was noted that the succession of (? nuclear) power plants down the Rhine in Germany led to the water getting to 30 degrees C by the time it left the country at which point only goldfish would survive in the river it was suggested. Not good news for Holland either.

[Anastasius]

Perhaps not ....

How so ? Just curious. The physics behind condensing boilers and the temperatures that they need to run at for condensing is well documented.

[Anastasius]

Indeed, and given the small size of so many houses in this country the chances of condensing boilers ever having a long enough pipe run to lower the return temperature enough in an ordinary radiator CH system are low to non-existent, even taking into account rubbish insulation levels.
Some years ago there was an open house type scheme here over about 4 years run in conjunction with Heritage Open Days which gave the opportunity to see various types of 'green' and alternative systems - heating, power generation, water management etc - in real homes, and to talk to the owners. Although obviously things have moved on for some of the technologies the basics still hold good and hearing about the pros and cons from real people using them rather than salespeople is invaluable - and also really interesting in many cases since the people involved were by definition slightly out of the ordinary.

It's not the return per se. The boiler needs to be running at around 65 degrees and not the 80 degrees that most people run them at.

[oddoneout]

It's not the return per se. The boiler needs to be running at around 65 degrees and not the 80 degrees that most people run them at.

Yes sorry, I was forgetting things have moved on, but when we were looking into it the boilers at the time needed the water returning to the boiler to be 'cool' enough to trigger the condensing part of the system, but it rarely was which made the boiler inefficient. I suppose a big advantage of the modern boilers is they remove the need to worry about where the flue outlet goes as it's just water vapour - or should be.

[Dave2002]

It was a new build on a big site with loads of space for the GS pipe runs. I got the impression that the installation tried to follow the rules but somehow didn't deliver the intended results, perhaps too early an adopter with no expertise behind the installation?

Controlling an underfloor heating system can be difficult. I think too few people really understand how they work, and even knowing some of the basics doesn't help, as one has to know more details, such as the mass of material which is under the house (or floor - if it's not on the ground level) which retains heat. Turning the heat up doesn't really work well, as there will be a substantial delay while the heat builds up, and then there will most likely be an overshoot effect which some people may find uncomfortable. To some extent personal tolerances come into play. Some people only like to have temperatures in a fairly narrow range, while others may be quite happy to have high temperatures, or may not be too perturbed by low ones either. That's why I suggested having underfloor heating, supplemented if necessary by fan heaters to give a quick burst of heat. An added complication is caused by the siting of room thermostats, which can be affected by supplementary heat sources.

Underfloor heating does work, and can be economic, but has slow response times which can be difficult to live with, and many people (including myself sometimes) find them difficult to understand or control. Heat pumps should easily be capable of running an underfloor heating system if it's well designed, but one has to learn to cope with the slow response. Some automated systems may manage to predict the load demand well enough to be helpful, but some may be so difficult that users really don't like them - being too cold when they want to be warm, and too hot when they want to be cool. The response lags do need to be offset carefully.

Rapid changes in weather conditions are also sometimes not helpful for systems with significant response delays. Some systems try to be predictive, but then they may rely on weather forecasts - which as some of us know - is not a guarantee of success, whereas waiting for the weather changes to happen - a feedback method - can be too slow.