Harry’s Garage

[V8Granite]

We use the sonic readers and use 2400 cubic metres per hour.

Dave!

[mik]

@V8Granite You win forums biggest boiler Dave.

[V8Granite]

When I’m a gazillionaire, I may just install one of our engines to keep my tropical fish lake warm.

Dave!

[KiwiDave]

What is the main source of fuel for NZ electricity generation?

Some solar, some hydro, lots of geothermal and the rest made up by coal power, which of course they're trying to reduce. If I remember rightly there's new geothermal and massive solar farms coming online this year.

And I've just been back to my bills, we're billed in kWh, so averaging around 11,800 kWh per year since solar/battery was fitted to the house. We both work from home, and I'd say either heating or cooling via heatpumps (four hi-wall mounted units, two external condensors) for 70% of the year. No EVs. Six bed house.

[Marv]

Wallabies?

i think they’re a non-native pest over there, so probably all for using them as fuel!

Wallabies, Possums, Hedgehogs, they chuck them all in the furnace.

Dave, sounds like the heat pumps in your house are air to air?

If so, do you heat your DHW via immersion or some other means?

[KiwiDave]

Yes air to air. As we're on the edges of the sub tropics we don't really need to worry about their drop off in performance when it gets cold. There were a few times when I lived in Wellington where you could tell they were struggling to do much.

Hot water is an immersion heater yes. 3kW element.

[Jobbo]

Is built in cooling a common thing in NZ? And is your house pretty efficient because it seems relatively low use for a 6-bed place.

[KiwiDave]

It's probably more that heat pumps have a pretty high market penetration, and all heat pumps are heating and air con. I've only been in one house here with gas central heating (in Wellington) which cost them a fortune to run, and only been in three with central heating at all. The other type uses a heat pump for the heating aspect. Other than that it's heat pumps or wood burners. There's actually still a large amount of homes use stand up, plug-in oil heaters. Of those options, heat pumps make by far the most sense, and the wall mounted units (either hi-wall or floor standing) are pretty easy to retrofit to houses. Building standards have only really got half decent in the past 10yrs, now specifying insulation and double glazing etc. Causes its own problems because in the warmer areas the houses can't breathe and are forever full of humidity.

Our place is so so - it faces North so gets all day sun into the main living area through glass across the whole front of the house. That front part is the only part with double glazing but there are parts of it where you could poke a pencil through the gap to the outside as the huge doors have sagged a bit. We only fitted underfloor insulation in the past six months and the roof has none. So by Scandinavian standards say, it's woefully inefficient. We use the bedrooms as 2x bedrooms, 2x offices, drum room and the room where the dog sleeps in her crate/extra wardrobe space/have an ironing board set up. We also run a dehumidifier every day downstairs. I'd say the 'low' usage is probably that in general Auckland is 15-25 degrees temperature. It occasionally gets down to single digits in winter and 25-35 does happen in summer. We just don't spend huge amounts heating the place. That and there's only two of us plus dog living here

[Jobbo]

I think the heat pump installations in the U.K. which are now becoming more common tend not to have cooling - seems very short-sighted to me.

[Marv]

I think the heat pump installations in the U.K. which are now becoming more common tend not to have cooling - seems very short-sighted to me.

I think you're right that it's not an option on most heat pumps installed in the UK.

The Samsung air-to-water heat pump I have, has the capability of cooling. No idea how and it's all switched off/greyed out as an option on the controller.

Not sure how well cooling would work with rads and underfloor either?

It's not a thing that concerns me much, our heatwaves are very fleeting

[integrale_evo]

It depends how they’re hearing the house. Our barn uses an air source heat pump and has no problem working in sub zero conditions maintaining a nice even heat inside. Triple glazing with decent amounts of insulation and underfloor heating.

No cooling function but I’m not sure cooling the floor down would make a massive difference to the internal temperature other than making it uncomfortable to walk around on.

A bit different to the heating and cooling ac units bolted to the wall in my work office which have been on regularly this season unlike the previous cooling only units which were only used a few days a year.

A lot of heat pumps have been badly sold to misinformed people. People are so used to oil or gas boilers which don’t run that often but give a big burst of heat and roasting hot radiators when they do, and expect a heat pump to be a direct replacement.

[jamcg]

I think the heat pump installations in the U.K. which are now becoming more common tend not to have cooling - seems very short-sighted to me.

If it features cooling it doesn’t qualify for grants. You can get £7500 towards an air to water heat pump or ground source only.

I agree that the air to air is short sighted, as they’re simple to install and relatively cheap, and can do multiple rooms like old school warm air heating, with the benefit of ac added in.

However the biggest oversight isn’t the air to air though. It’s the hybrid systems. Perfect for homes where an exclusive heat pump system isn’t suitable, but where it would work 80-90% of the time. The rest of the time that’s helped out by a gas boiler, so it’s much more effective and cheaper to run than the system switching to immersion backup- imagine the cost of running a 3kw immersion heater to run your radiators

[IanF]

What’s the life expectancy of the heat pumps these days? It seems to me that they will probably need replacing before they’ve paid for themselves.

[Marv]

What’s the life expectancy of the heat pumps these days? It seems to me that they will probably need replacing before they’ve paid for themselves.

I remember at work speaking to one of the engineers in Sweden about some software… he was telling me that some people were round his house that day replacing his heat pump, as it was tired after ~20 years.

As he’d put a few extensions on his house, it became undersized.

IIRC he was in the northern part of Sweden too.

I think (and hope ) they’re pretty reliable.

Having worked in IT for several decades, the only failures I generally see on the air-to-air units (for cooling server rooms) is the small motor which pumps away condensation.

I briefly looked into it, and if it wasn’t for tariffs introduced by you-know-what, it we would be cheaper to buy a heatpump from Sweden. They are over priced here, so yeah the return on investment is a bloody long time, just like with solar and batteries.

[KiwiDave]

Keeping them serviced and maintained seems to be key here, but you see plenty of them around which have to be 20yrs plus. All the plastic yellows

I think the cost of them and the time to pay back must be very different here, simply because you're weighing it up against plugging in bloody oil heaters and burning $20 notes for your own amusement. But for the record, four hi-wall internal units, two large compressors outside and a rather custom fitting to hide the majority of it which made a three day install was $11k, so what's that £5500?

[Jobbo]

Not sure how well cooling would work with rads and underfloor either?

That is a good point Marv (and Harry) - I hadn’t really thought about how a heat pump in the U.K. actually heats the house And I’d not realised they wouldn’t qualify for grants if they did cooling.

Our previous house was built in the 1960s and had big windows, the main bedroom getting rather warm in summer even if we kept the windows shut. I always thought an a/c system just serving that room and the living room below would have been useful, and if you install a fairly standard split a/c system I’m fairly sure that would have the ability to warm as well as cool - hence the idea.

We have a mobile a/c unit now at our new house which worked well at keeping the main bedroom cool last summer. I think a fixed split a/c system in the kitchen/diner would be useful too, since that has south facing bifold doors and a roof lantern so gets rather warm in summer. But that can wait.

[IanF]

Interesting.. €130k for a Coxster!! Jesus!

Plus new RRS for Harry.. he really likes red ones!

[Barry]

That French taxation table was just disturbing.

[Jobbo]

Makes me feel less annoyed that our Cayenne is going to cost £7000 in first registration tax if it arrives in April and half that if it arrives in March. If it was £70,000 I would have cancelled the order I had no idea the French regime was so punitive. Basically that means plenty of cars will simply go off sale because nobody is going to buy them.

If that tax regime were to become commonplace it's irrelevant what the manufacturers want to build; they'll have to switch to EVs. I do think Harry's PHEV love is almost entirely due to the tax regime in the UK, and that's surely not going to stay the stay as it is. One of the reasons I've avoided getting an EV or PHEV through work is that there's too much uncertainty about what will happen to the tax on them in a couple of years.

[V8Granite]

It’s a silly thing as when the Vauxhall Amperage arrived, if you didn’t need an estate it was a fantastic vehicle to be good for local air quality, commuting cost and all round practical uses.

Dave!