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Heat pumps of the 1800s are becoming the technology of the future

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Re: Heat pumps of the 1800s are becoming the technology of the future

#241

Post by fifteenforty »

IAmGraydon wrote: post #232
fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

Are you asking why the Daikin Alira X is more expensive in the US? It's because it's not a brand that is normally found here. If you went with a common US brand you can get a good system with 4 units and a 36,000 BTU heat pump unit for around $6,500 USD installed. I don't love the wall units - they're pretty ugly, even the new ones. If you're getting a mini-split, the in-ceiling or wall cassettes that are hidden are…

In the Australian market, the efficiency of the in ceiling or in wall units is lower than the high wall units. They are also much cheaper to buy and install.

Re: Heat pumps of the 1800s are becoming the technology of the future

#242

Post by cbrozefsky »

1123581321 wrote: post #214
cbrozefsky wrote: post #90

Earlier quoted context omitted.

They are now. In Vermont, we are in our first year with heat pumps. Have a wood stove as backup and supplement when we want to go pantsless mode. The original oil burner is currently turned off, out of commission waiting on some parts. We could go without the wood stove, and have done so for stretches. We installed Mistubishi Hyperheats, 3 external units, 5 heads. Zero interest financing by installer, for about 21k a…

I'm curious about the disposition of the local HVAC companies and tradespeople there. Do you feel confident that you could get emergency service in cold weather? I like this technology a lot, but I live in an area where I can't get most companies to take my request for a quote seriously if it's not a standard central air, furnace or water heater. I had to DIY my Rheem heat pump water heater in 2021 because I couldn't…

All the ones we know of are doing mini splits and heat pump hot water, and we had no problem getting quotes and even recommendations.

Re: Heat pumps of the 1800s are becoming the technology of the future

#243

Post by bumby »

Brybry wrote: post #199
fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

I don't think the hardware is that expensive in the US, it's the installation (which costs more than the hardware). And mistakes by installers will cost even more. Our installers didn't flare a line set connection properly and it leaked slowly and that was a very expensive bill (especially since refrigerants have changed so much). Our Daikin indoor units have also had condensate leaking issues, probably due to poor i…

>And mistakes by installers will cost even more.

I once looked at a house with a new GSHP horizontal loop installed in the desert southwest US. I talked to the installer and they said the loop was only 12” deep. There’s no way the ground maintains steady temp at that depth, meaning you’re losing efficiency in the hot months when you need it most. Not to mention thermal pollution which will exacerbate the problem and the risk of hitting the loop with even minor ground work. They were adamant it was a good design.

Unfortunately, many installers jump on the bandwagon without the necessary expertise.

Re: Heat pumps of the 1800s are becoming the technology of the future

#244

Post by jdmichal »

elil17 wrote: post #85
jdmichal wrote: post #37

Earlier quoted context omitted.

Unless you have a very strange setup, centralized A/C does not have humidity sensors nor run just to dehumidify. Nor does removing humidity increase the load on the A/C system. Removing humidity is just a happy by-product of how centralized A/C works. So no, you would not be increasing load for that reason.

The above comment is incorrect, even for systems without integrated dehumidifiers. AC systems absolutely do have a higher load with higher humidity because ambient water will condense on the evaporator coils if the dewpoint is higher than the evaporator temperature (which it typically is). That said, it still may be more efficient to open your windows, depending on the humidity.

I stand corrected. Apparently 60% humidity or so is the line. That said, I live in Florida and haven't ever had an issue, but maybe that's because the A/C runs so much anyway...

Re: Heat pumps of the 1800s are becoming the technology of the future

#245

Post by Dylan16807 »

elil17 wrote: post #169
maxk42 wrote: post #105

Earlier quoted context omitted.

So can heat. That's not the appliance's fault.

It's not about fault at all - I'm just saying that the analysis does not apply to lightbulbs. For a lightbulb to be as efficient as a resistance furnace at heating a room, you would need to have zero light escape that room so that all the light would be converted to heat. Then, the heat would leave the room at the same rate as heat generated by a resistance furnace. Even if we consider incandescent light bulbs, which…

Thermal infrared doesn't go through glass. You only lose a negligible amount of visible light. It's still 100% efficient as an integer percent.

Re: Heat pumps of the 1800s are becoming the technology of the future

#246

Post by Scoundreller »

mixmastamyk wrote: post #115
Scoundreller wrote: post #97

Earlier quoted context omitted.

The smart thing to do in winter is put municipal liquid water in your freezer, and dump it outside once frozen to thaw in spring. Rince repeat all winter long. Voila: everyone has heat pump heating! (And dead compressors). The dumb thing is having the compressor itself indoors in summer. Should be outside.

Interesting, how to remove it easily from the container? Or do you use an ice machine? Is this more efficient than using the heater? Guess it uses heat pump tech.

Just have tubs of water. Dump them once they’re ice.

Yes, more efficient than a resistance heater. Possibly more cost efficient than gas.

Wastes a lot of water (if you don’t have a well).

A fridge is just a heat pump.

Re: Heat pumps of the 1800s are becoming the technology of the future

#247

Post by jdmichal »

JustSomeNobody wrote: post #61
jdmichal wrote: post #37

Earlier quoted context omitted.

Unless you have a very strange setup, centralized A/C does not have humidity sensors nor run just to dehumidify. Nor does removing humidity increase the load on the A/C system. Removing humidity is just a happy by-product of how centralized A/C works. So no, you would not be increasing load for that reason.

My thermostat allows me to set the humidity level at which it will turn on the A/C to deswampify my southern home.

Interesting. But I assume it's not a separate function from cooling, right? It might just over-cool the house in order to meet the humidity target?

Re: Heat pumps of the 1800s are becoming the technology of the future

#248

Post by thehappypm »

teruakohatu wrote: post #114
fifteenforty wrote: post #112

Earlier quoted context omitted.

You have to think carefully about where you run the ducts. They can be a huge source of energy loss. 40% is the number quoted by the EPA. Most roofs in Australia still aren’t sealed. The air barrier and insulation barrier is the ceiling. The roof space itself is not insulated, so the ducts are exposed to extreme temperatures, thus destroying the efficiency. Here is just one article on it: https://newenergythinking.co…

I hadn't considered that. My argument with split systems, at least how they are installed in NZ, is that they are usually installed in the main living area and if there is a second unit, in a corridor. So corridors are heated or cooled far hotter or colder than they need to be in order to heat/cool bedrooms.

I have two units that are heated by heat pumps in Massachusetts.

One has mini splits. You definitely don’t generally put mini splits in every single room (like bathrooms or interior hallways) because each mini split requires tubing, is large, and expensive. No, I think it’s way more likely that you would have them in the bedrooms rather than the hallway

Re: Heat pumps of the 1800s are becoming the technology of the future

#249

Post by AOsborn »

teruakohatu wrote: post #110
fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

> Ducts are dead. Ducted heatpumps are a thing here in NZ and make sense to me, not that I have used one. The heatpump sits in the roof and air is pushed into three or so rooms through ducts. If building a new house I think ducts would be the way to go.

I thought this was absolutely the solution but backtracking a little now based on experience so far.

We have a two-level, five bedroom new build in Auckland which came with a single-zone ducted system. So outputs are the bedrooms plus upstairs and downstairs lounges. The vents are tidy and unobtrusive - much less space than a wall unit in each location.

We're having major issues balancing the temperature across the different rooms as there is one thermostat.

Think setting the temperature overnight for one room with a couple plus a cat vs another room with one of the kids. Basically the wife and I are always far too hot because otherwise we're freezing all the other rooms. Or setting a reasonable temperature in the lounge makes all the rooms icy in short time.

I'm now thinking about forking out the couple of thousand to get a small heat pump installed directly into our room so we can run it separately from the rest of the house.

So if building from scratch, either look into a multi-zone system or separate heatpumps. If you can get separate systems but hidden in the walls/roof that would be the best.

Re: Heat pumps of the 1800s are becoming the technology of the future

#250

Post by _carbyau_ »

TheSpiceIsLife wrote: post #209
fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

This is exactly the same setup I have here in Launceston. Another great thing about having three seperate units is if one breaks, rare as it is, you're not stuck without heating / cooling.

I am leaning more to this solution for this reason. Trying to get any tradie quickly these days doesn't happen. Trying to get an aircon person in an Australian summer is worse.

I despair for the rental market right now. High prices and landlords are generally crap at amenities they don't personally use.

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