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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

#481

Earlier quoted context omitted.

Was there anything beyond the extra time/effort that made you regret going with a non-DIY model? I’m considering doing the non-DIY in next year or so.

No, not at all. I enjoyed it but my wife had a different expectation of completion date than I. My advice is to get the tools, don't shortcut, so that you have confidence at each step. Stuff I had already specific to HVAC: -R-410a manifold, gauges, and hoses. Stuff I went out and bought: -Nitrogen tank pressure regulator and hose for HVAC. -Mandrel pipe bender -Flaring tool -Micron vacuum gauge -A slightly better cop…

Thanks for the follow up! I understand completely. Somehow my wife stuck with me after more than a few significant home projects with misaligned expectations around completion. Re: wall mounting vs pad. Do you find noise transmission to be a nuisance?

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

#482
post #274

Earlier quoted context omitted.

> Ducts are dead Great. You just eliminated approximately 15% of lazy screenwriter tropes for thrillers and action movies. Now they are forced to rely on replacing live surveillance camera feeds with a loop.

No one is crawling through house ducting

TELL THAT TO THE LAZY SCREENWRITERS

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

#483

Earlier quoted context omitted.

If it's pretty cold outside, then you're throwing all of the ostensible energy savings of a heat pump out the window the minute you open it to air out the house. Following the thread of conversation, it just didn't compute to me: >>>> Heat pumps are great for climate control >>> Yeah, ducts are dead >> What if you want to recirculate air in your house through your central air filter to eliminate smells? > Just open t…

I'm not sure why "Heat pumps are great for climate control" went to "ducts are dead". I live in Florida, we've used Heat Pumps for as long as I can remember. We also have central air handlers with blowers and ducts to distribute the conditioned air. Mini-splits can _also_ be ducted mini-splits. According to my HVAC geek friend, mini-splits are pretty terrible about humidity control (an important thing in Florida). Fo…

The Melbourne climate I was referring to needs heating 9 months of the year. The vast majority of houses have very simple, inefficient gas ducted heating. Rightly or wrongly, humidity control is generally not well considered.

I was going to install an ERV system but the payback was not within the life of the equipment.

Someday I’ll build a Passivhaus with a system as you describe.

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

#484

Earlier quoted context omitted.

For an existing dwelling, the best solution is probably mini splits (wall mounted) combined with decentralised heat recovery ventilation as required. Ducts running in an insulated space are sources of huge energy loss.

*uninsulated

Yes correct! Thank you!

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

#485

Earlier quoted context omitted.

Honest question: Why would one care about cold or hot spots on the ceiling? I don't spend much time up there.

Because in the winter the thermal energy within your room will “flow” out of those “cold spots” at surprisingly high rates; in summer those spots act as space heaters. In both scenarios they will adversely affect the ambient temp of the room. In short, whatever method you use to heat/cool the room will have to work harder and will take longer. Here’s [0] a good overview of heat flow in this context, with some hints t…

I might be totally misled, but I think of it as a parallel resister circuit. One area of low resistance is extremely significant.

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

#486

Earlier quoted context omitted.

Mid-efficiency furnaces are still commonplace in the US, and they don't have sealed combustion systems - they get combustion air from the indoor space, but they vent 100% of combustion products out. High-efficiency furnaces in the US made in the past 30 years or so use sealed combustion with intake and outtake to the outside. (North American high efficiency furnaces older than about 30 years were not necessarily seal…

> But yes, the GP is full of shit. Or you live insulated from shitty alliances and low income life. A friend's husband was killed by a faulty boiler, carbon monoxide poisoning. In 2015 I lived in a house where boiler ignition didn't work and you had to reach inside with a lighter. That unit was definately not sealed. UK only required consenser boilers since 2005, the ones before that used to air from inside your hous…

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

#487
post #39

Earlier quoted context omitted.

Is the AC dehumidifier an extra feature/task, so actively followed, or is it doing dehumidification just as a byproduct happening while cooling?

Some AC units have two modes - cooling and dehumidifying. When in cooling mode it will blow a lot of air to keep evaporator as hot as possible, so less humidity is condensing on it (but there will still be some). In dehumidifying mode it will blow less air but keep evaporator cool, so more condensation for the same amount of air cooling.

Do you have any source for this? It's a topic I've always wanted to understand better. Especially, it's not clear which mode consumes less.

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

#488

Earlier quoted context omitted.

Some AC units have two modes - cooling and dehumidifying. When in cooling mode it will blow a lot of air to keep evaporator as hot as possible, so less humidity is condensing on it (but there will still be some). In dehumidifying mode it will blow less air but keep evaporator cool, so more condensation for the same amount of air cooling.

Do you have any source for this? It's a topic I've always wanted to understand better. Especially, it's not clear which mode consumes less.

Source - I have Kaisai mini-split at work and I've observed how each mode works (with my hand). There's probably more energy used per cooling amount during dehumidifying, because it's bigger temperature differnce (which means lower COP) PLUS condensing water (water phase change energy is big).

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

#489

Earlier quoted context omitted.

> 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 d…

always good to have zoning, either via small separate heat pump or with a retrofit like AirZone (not sure if something similar is available there) which modulates the flow to each duct from the air handler.

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

#490

Earlier quoted context omitted.

> you isolate yourself from nature That's a feature not a bug. > This hermetically sealed environment that we create for ourselves is bad for us. Not at all. Heat recovery vents exist for a reason!

Not physically. Bad for our souls.

My souls feels unhappy when we waste a lot of energy and destroy the planet.
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