Stones

I'd also suggest comfort comes into this, and what type of heat you want. How an A2A delivers vs an A2W via UFH. I personally dislike warm air being blown around by an A2A, but when on holiday, appreciate the cool breeze of aircon. Heat delivered via UFH from our A2W gives a nice steady even temperature in house (with the added benefit A2W provides my DHW needs as well). But the cooling is less effective as it takes longer (albeit very pleasant when up (down?) to temperature. I think A2A are fantastic in large rooms / open spaces, less so in small(er) rooms. Like everything else, there are trade offs, and individual lifestyle requirements, and house location / design all play a part.

If memory serves, the original Passivhaus heating standard was designed so that all of the additional heat requirement could be delivered via a ventilation system (resistive heater). I know someone here who designed specifically to Passivhaus accreditation level, but still requires additional heat on certain days. Average solar gain for example is all very well, but rarely do you get the gain evenly spread. When I was looking at it for our house (2016), I looked at a range of options and heat requirement levels. The conclusion was that for both heat and DHW requirement, if the requirement was below 2500kWh annually for each, you would over a 10 year time frame be better off using straight forward (and inexpensive) resistive heaters. Above that level of requirement, the figures stacked ever more favourably in the direction of a heat pump. Energy prices have of course significantly changed since, so the cut of kWh requirement point will have changed.

@Steve W Appreciate this relates to fans in a Vent Axia, bit hopefully give you the push to try bearing replacement.

Would you mind sharing how much the course cost you, and any registration fees you need to pay?

Although I imagine the challenge given the postage stamp sized gardens is where would the ground pipes go. As you rightly point out a borehole would solve this, but how many GSHPS can a borehole support - presumably as you also say, local geology dependant

We went out of interest to have a look at a new development outside Inverness (Tormagrain). No heat pumps, all gas. When I questioned this, they said they had been refused permission for heat pumps, on the grounds of noise - apparently the combined effect in the house layout pattern would be over 100db. The only way they could have a heat pump based system was to install a communal one (think large supermarket or warehouse size provision) and locate it away from the houses. High overhead cost, (albeit not insurmountable) to manage that - invoicing etc, and lack of support to maintain and service such units/systems apparently.

Thanks all.

Do you happen to have anything in writing from the course confirming that?

Interested to hear what users have been required / requested to submit in the way of plans / details for accessibility ramps beyond providing a written specification (including ramp geometry) and marking on site plan. Has anyone been required to submit additional drawings / sections / calculations?

I've got an acquaintance installing one of the following small hot water heaters in a portacabin style building: ATC-Pacific-Unvented-Water-Heaters.pdf The installation info shows the discharge point post tundish as 'to drain'. The project in question requires a building warrant due to the length of time the building will be in place, and therefore needs to comply with the relevant section of the most up to date (Scottish) building regulations: 4.9.4 Discharge pipe termination: The pipe termination should be in a visible location and installed so that discharge will not endanger anyone inside or outside the building. Ideally, the final discharge point should be above the water seal to an external gully and below a fixed grating. Other methods for terminating the final discharge point would include: a. up to 100 mm above external surfaces such as car parks, grassed areas, or hard standings; a wire cage or similar guard should be provided to both prevent contact with discharge and protect the outlet from damage, whilst maintaining visibility b. at high level into a hopper and downpipe of a material, such as cast iron, appropriate for a hot water discharge with the end of the discharge pipe clearly visible c. onto a flat roof or pitched roof clad in a material capable of withstanding high temperature discharges of water, such as slate/clay/concrete tiles or metal sheet, with the discharge point a minimum of 3m from any plastic guttering system that would collect such discharges. Discharge at high level may be possible if the discharge outlet is terminated in such a way as to direct the flow of water against the external face of a wall. However evidence of the minimum height of the outlet above any surface to which people have access and the distance needed to reduce the discharge to a non-scalding level should be established by test or otherwise I recall from previous discussions that some users had been able to terminate the discharge to a drain inside their houses rather than externally. I'd be grateful if someone could advise what they did / if BC accepted?

There was something on the local radio last week about this. In short, the way the payment has been set up (for speed of payment rather than accuracy) they are using simplified data to determine areas that are not connected to the gas grid, and therefore alternatively fuelled.

To clarify, there is no intention to charge the domestic properties for any excess diverted from the commercial array. Clearly there would have to be legal agreement on who was responsible for the battery and tech that would enable this. In this case it would be the community company that runs the commercial business, as they would also be the landlord of the rented houses. Absolutely take the point if trying to sell to households for the reasons you have listed.

I'm involved with a local project that will be a mix of community commercial premises and housing for rent. One of the things we are thinking about is a semi combined / community PV and battery storage system - fitting as much PV as we can to the commercial buildings, and cascading surplus generation first to battery storage for the commercial buildings, then when they are charged, to batteries in the rental houses. The rental houses would have their own PV fitted, which would divert excess generation into a household battery and potentially a DHW cylinder. Each property, be it the commercial buildings, or the domestic properties would need to remain islands for billing purposes. Is this possible? - I can't see why not Would the domestic properties need two batteries - one for excess feed from the commercial building, and one fed from their own array? Has anyone experience of setting up or been involved in anything like this?

Is it just that window, or every window that you have condensation inside (when outside temp is as per you describe)?

@Barryscotland A friend has something similar to the set up you're describing. TV seems unnaturally high on the wall to me but that's something you can perhaps get used to. What they do have is a 150mm deep timber mantel over the stove position with a steel heat shield fixed to the underside.

Just checked mine, over the last two weeks the ASHP has used 105 kWh on heating (155sqm internal footprint, 50% full vaulted ceilings with an additional 15sqm attic type room - footprint is laid out as two interlinked cottages, so a lot of exposed exterior wall). This has delivered 387 kWh of heat to the house (so a CoP of 3.6). I have the master thermostat set to 19C - we are trying a lower set point this year to see what the energy saving is compared to previous set point of 21C. So far, so comfortable and the house sits around 19.5 - 20C. It can get higher, but that depends on the sun appearing. Ambient temp wise, not as cold here as elsewhere, but higher wind speeds, which ultimately have much the same effect in determining our heating requirement.

We have oak veneered MDF forming our window cills (trimmed with solid oak), and used for all the shelving (visible and within wardrobes), treated with 2 coats of Osmo Polyx Oil. 5 years in, no issues at all. Robust enough for day to day living and doesn't mark moving things around - generally books, ornaments etc. Should be fine on a wall.

@TerryE Really interesting Terry. I've been collected limited data for our build and have 5 years worth. Our heating input requirement, sits between 6500 and 7000 kWh per annum, so very close to you. We solely provide this via UFH, the heat source being our ASHP. Input energy required sits between 1850 and 2000 kWh per annum, the variation being down to difference year to year in weather. Our domestic electricity use (everything other than heating and hot water via the ASHP sits at 4000 kWh annually, albeit I can already see this reducing now our children are away and games consoles are not being played all evening). Our heating requirement is a little higher than I modelled, but not significantly so, and given the year to year variation in heating requirement, perhaps margin of error territory. We have up until now run our house with the master thermostat set to 21C, although in reality the house sits at 21.5C As an experiment, I've reduced the temp down to 19C to see how we get on and whether we are comfortable through winter. So far so good, and it's certainly very comfortable when you wear a jumper. Early indications indicate this change would halve our heating requirement.

I run my house as a single zone, using the FTC controller as the thermostat. The bedroom.have there own but they only open and close the individual loops in the UFH, they do not call on the ASHP for heat.

You'll have massive overshoot of internal temperatures at 45C flow temp. We are in an ICF build, and flow temps generally run between 30 and 35C. We also have a Mitsubishi Ecodan 8.5 kW with FTC5 controller, set at 21C target temp through winter. Personally, I'd use the auto function and target temperature on the controller and let it sort itself out.

Yes, vertically mounted, and can only assume when it failed there was as you suggest, a flame. None of the wires attached to the various pins had any damage (other than a couple with a little soot on the connector). What is the likelihood of it happening again - not sure. Given the relay that failed only costs a few pounds, it may very well. Hopefully with a completely new control module/ board the risk of repeat is less. In terms of fire, given there would appear to have been a small flame, I'm not sure what to think. The control board itself is.mounted on the back of the main body of the oven, and then covered by a metal panel, so in effect sits in a metal box.

Definitely a hole in the side of the relay:

Yes, replaced the board. Marital harmony demanded a prompt resolution. My question was really whether it was worth having a go at repair of the damaged board. It's 30+ years since I did any meaningful electronics so I'm a bit rusty.

The culprit! @ProDave - is this repairable / worth trying? Control module replaced and all working.

Any scope for crane and concrete skip / hopper, or telehandler fitted with pouring bucket?