HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

If you are not fixed on bricks and mortar you might want to consider:
Straw bale: https://cat.org.uk/events/building-with-straw-bales/ and https://cat.org.uk/worlds-first-miscanthus-bale-house/ (miscanthus grows on marginal land - https://www.terravesta.com/)
Rammed earth: https://cat.org.uk/sustainable-architec ... -building/
Cob: https://cat.org.uk/events/cob-building/

I have a straw bale house. A friend and i built it about 20 years ago. Not sure that 1/2 a straw bale house would work that well, especially if you aren't keen on plastering.

The heatpump i installed for mid-season heating was almost useless, the foggy and very cold climate cause the external compressor unit to turn into an iceblock when it was needed most. I can't see any technical fix for this, the continual defrost cycle drove me nuts, you just can't extract much heat from freezing cold fog.

What i would suggest is you consider minimizing heat transference by building an inner frame separate from the external one, connecting them together with something that doesn't transfer heat well (like plastic or pinus radiata), not steel. Get double glazed windows with a thermal break. Consider rodent proofing with stainless steel. Get an efficient wood fire, use dry wood. Maybe embed hot water pipes in your concrete pad.

r3xj0hn570n - interesting what you say about the heat pump that you installed - it is possible to get them to work in Scandanavia: https://cbey.yale.edu/our-stories/renew ... candinavia. If you have particular issues a ground source heat pump might be better and worth the extra cost. I wonder whether your system was installed by an MCS accredited installer - they do have to be done correctly. Could you tell us more about your installation? The couple of thousand installs discussed in the video that I linked appeared to work and save people money if used as suggested.

As you indicate a part straw bale would be more complicated and would need someone with expertise and good professional indemnity to advise.

Underfloor heating as you suggest is the best sort of heat emitter with a wet heating system - especially for heat pumps. Unless you have ready access to your own wood or local wood for a fire I would not suggest relying on a wood fire - perhaps except very cold days but a cheap infra-red panel might suffice for that.

Being a part time farmer I have loads of wood from a seven acre woodland which is supplemented by the tree surgery work I do. I have a log burner which gets used everyday October to end of March. We get through quite a pile of wood every year. My wood burner is not a boiler stove as connecting it to the oil boiler system looked a bit of a headache plus I didn't want to install a thermal store due to the space it takes up and I can't sleep at night knowing there are water tanks in the roof space.

Bales are something I have a lot of . But I am not comfortable doing it myself and this is a diy project. Plus the wall might be a bit thicker than I would like. I love the idea of it though.

Been dressing some random stone today to 4" thickness. Done a fair bit of stone dressing in my time. There is definitely an art to it I have had enough practice to be good at it. This stone is limestone from an old farm building that got pulled down in the 80's and has been sat in a pile ever since. I actually really enjoy dressing stone, must be the caveman in me There is some satisfaction in taking an irregular shaped stone and making it a good shape for building.

EcoFreek wrote: ↑Fri Jun 24, 2022 11:15 am I wonder whether your system was installed by an MCS accredited installer - they do have to be done correctly. Could you tell us more about your installation? The couple of thousand installs discussed in the video that I linked appeared to work and save people money if used as suggested.

I installed the heatpump according to the manufacturers instructions. My house is on the outskirts of a small rural community hours drive from the nearest centre, so no 'accredited' installers.

I'll be more specific about the issue. The external evaporator heat exchanger, in trying to absorb latent heat from the air causes moisture in that air to freeze onto the evaporative surface. All the things i tried to mitigate this behavior had little effect. The built in defrost cycle kicked in, using electricity to heat the external evaporator. I suppose a smarter unit could automatically limit the amount of heat being extracted to just below the frost threshold, but doing it manually (as i tried) resulted in very limited heat being extracted. An in ground heatpump will not suffer this issue.

That said, on cool clear days the heatpump worked as advertised, ONLY when the air was near freezing AND foggy that it all turned pear shaped. Unfortunately, the prevailing climate in winter there is a cool foggy air layer sitting in a river valley. If your winter climate is like this, an air to air exchange heatpump is not for you.

I no longer go there in winter. It's my favourite spot in NZ in summer, i just can't handle the winter there at all.

karatestu wrote: ↑Fri Jun 24, 2022 7:35 pm Bales are something I have a lot of :dance: . But I am not comfortable doing it myself and this is a diy project. Plus the wall might be a bit thicker than I would like. I love the idea of it though.

They need to be straw bales, i used barley straw. The walls end up 1/2 metre thick which makes window installation interesting. Walls can be infill or structural. My next building was barn style outer walls connected to standard 90x45 internal framing and LOTS of fibreglass. Unfortunately rats got into it, despite lots of precaution. I hate rats, they ate the wiring of the freezer room i built there and i lost thousands of $ worth of food. Anyway, this construction was just as warm as the straw bales.

All interesting stuff.

Karatestu - it might be worth going on a course on straw bale so that the project was less DIY - perhaps before that contact the course tutor and outline your plan in some detail - if they say no it is a no - if they say yes it becomes a maybe.

r3xj0hn570n - hopefully there have been enough experiences like yours now to point specialist accredited installers towards ground source heat pumps in a scenario like yours. Not my specialism but I think in the UK now if an ASHP will be kicking into the defrost cycle to regularly it will switch over to simply resistance heating - I think they are pretty smart at pushing the boundary before that though. Which given how variable the weather is in the UK should be fine; however, in a scenario like yours 'ye canne change the laws of physics, Jim' as Scottie might have said. The benefits of having an accredited installer with professional indemnity insurance - everybody learns something and nobody is out of pocket too much.