Heating systems in PH/Gold standard homes

[David Olivier]

I can't find any other threads with “auxiliary heating”.Was this gossip at the 11th. PH Conf.?

PHI have always strongly advised not turning off the heating if a family go away for a week or so, since a low-powered heating system can't heat up a building rapidly. (The fuel saving is trivial, especially as condensing boilers – still more so, heat pumps – are more efficient at part load than full load.)

If you do insist on turning it off, it's inconvenient to return to a cold house which will stay cold for days and you might resort to using portable electric heaters to aid the heating-up process.

My only qubble with PH is that when you get deep into the figures measured on some PH buildings, some of the quoted percentage savings are a bit over-optimistic.

I can't see a problem in using these tools to predict the energy use of non-domestic buildings. Larger ones are almost by definition occupied by a pretty random sample of human beings, whose variation in thermal comfort requirements and attitude to visual discomfort could be allowed for. If they're not, predictions may be wrong.

The notion that people in all buildings will behave in unpredictable ways which will frustrate the designers is naive. The designers may often have provided features which predictably annoyed occupants, such as S-facing rooflights (giving high winter heat loss and high summer heat gains). Usablebuildings.co.uk has plenty of useful papers/articles.

David.

[Mark Siddall]

David,
I'm a regular at UseableBuildings wedsite, and Adrian Leaman kindly came and made a presentation in our office not so long ago (one of his rare trips into an architects practice as I understand it.)

Design teams do have a tendancy to over complicate (and then not explain) the systems installed. I agree simple systems are what is required and robust flexible environments are key.

Mark

[Nick Grant]

David

Perhaps I posted it somewhere else or imagined I did but reference is:

'Heating and Ventilation in the “Building of Tomorrow”; Studies on User's experience with ventilation and heating systems in low-energy and passive houses'

Austrian Federal Ministry of Transport, Innovation and Technology. 2004

Which said (less than the title) 'Only 16% of users participating in the study rely exclusively on the ventilation system for space heating.'

http://www.nachhaltigwirtschaften.at/results.html/id3581?active=

Took me an hour but I found it and can now read German. Looks like lots of other interesting stuff, eg the S house.

Nick

[Mark Siddall]

Hey hey Nick. It looks like I can read German too 😉
Nice find by the way.

Mark

[Mark Siddall]

Nick,
Initially I was surprised that in Austria just 16% of the surveyed respondents rely exclusively on the ventilation system for space heating. I wondered i) does this mean that this mode of heating is unsuccessful? ii) does it reflect the fact that people are playing safe and distrust the new fangled technology? iii) or alternatively, reading between the lines a little with David’s posting above, perhaps people are disregarding the PHIs advise and have determined that they require/desire the rapid response of the more traditional heating system. On further review of document it would seem that the surveys covered both low-energy homes and PH standard homes, so with regard to auxiliary heating in PH homes this muddies the water somewhat.

As I understand it only PH/Gold standard homes can support an all-air heating system (the heat loss from a low energy home is to great.) As we’ll probably never know the answer, rhetorically speaking, how many of the surveys respondents resided in PH homes was it the 16%? What percentage of PH homes are heated using an all-air system? From what I’ve read the most economic heat distribution system in a PH is to use the MVHR as the heating supply (avoids the unnecessary expense of central heating). As a consequence I would expect that the proportion of all-air heating systems to be that much greater in the PH market.

The survey also reports that 44% of homes combine space heating via ventilation system with a supplementary heating system. That totals 60%, so what is going on with the rest of the heating systems? Presumably by central heating alone, after all why pay for two heating systems?

In Germany is would seem that Combined Service Units (CSU) have 30% of the PH market. As I understand it CSUs were specifically developed as a PH technology but are now being retrograded for use in low energy homes. As a result some manufacturers do supply units that are not only based upon all-air heating systems, rather they also include more traditional central heating systems. When seeking to interpret the adoption of CSUs within a PH market this retro-grading of the units the stats a little murky because. For more on CSUs: –
https://aecb.net/forum/index.php?topic=794.0

With regard to all-air heating in PH, and therefore Gold homes, it is interesting to note that the survey reports that control options for the regulation of these systems, have not yet been fully developed (improvements required especially in flats etc.) For any innovators out there it is suggested that the optimization of user interfaces and IT networking of the various controls, as well as options for single-room regulation, may contribute to the further improvement of ventilation systems. For more on Heating by MVHR:
https://aecb.net/forum/index.php?topic=323.0

Does anyone have any specific stats on the adoption of all-air heating with in PH projects?

Mark

[Mark Siddall]

Just to stitch a related thread together: –
https://aecb.net/forum/index.php?topic=959.msg3660#msg3660

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