Comment by KaiserPro | Hacker News Reader

Comment by KaiserPro | Hacker News Reader

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I think the single biggest mistake is differentiating HVAC from heatpumps. The second is not insulating

In the UK most newer offices use aircon to provide both heating and cooling. Its cheaper to put in, requires less maintenance and regulatory oversight.

However the biggest issue is that for any of your heating/cooling systems to work cheaply, you need insulation, and enough of it to do what you need. That means insulating floors, ceilings and walls. Moreover, having a bunch of thermal mass makes stuff a lot more comfortable.

My house is a 1930s semi-detached house. Think harry potter, english suburbia, and you'll get a good idea. It was designed to have an open fire in each room. This means that it has an airbrick in each room, plus a suspended wooden floor, supplied with, you guessed it, a fucktonne of air bricks. This means in its natural state, its windier than an open barn.

This means that with a 30kw boiler (8.4 tons or 100K BTU) working flat out for hours could get the house to about 19c (~66f) at best. Not only that but condensation clung to the walls, meaning a fucktonne of mould.

Combine that with huge south facing windows, meant that in summer the front room hit 37c(98f) with the blinds drawn.

Insulation and new windows with decent coating means that this summer (when outside was 40c) the livingroom's max temp was 27.5c this december we used 1500kwh of gas for heating. (compared to almost triple that in the house across the road.)

Insulation and air control are absolutely key to efficient heating and cooling, regardless of where you live. We built a stand alone guest house a few years ago. Insulated the entire envelope with closed cell foam to R25 in the walls and R60 in the ceiling. That means it loses or gains very little heat, but also means it exchanges very little air with the outside. It's heated with an 18,000 BTU air source heat pump, although for temps above 0C, just the heat of occupants does the job. To keep it dry and maintain fresh air, it has an outside air circulating system fitted with a heat exchanger. Highly efficient and comfortable down to -20C outdoor temps. Needs supplemental resistance heat when the temps are below that, but that's at most two to three weeks a year here in the upper Midwest. Solar panels make the whole thing carbon neutral in operation, averaged over the year.

Unfortunately, retrofitting existing housing that was not designed to be tight to this level of insulation and air infiltration is enormously expensive, if possible at all. We're getting there, one improvement at a time on our main house, but it takes a lot of check writing.

If your home is sealed tight, then you should consider either an ERV or HRV system as well, depending on the humidity of your environment.

They blow air out of your house and replace it with fresh air from outside, which a fan could do, but they include a heat (and moisture, in the case of ERVs) exchanging plenum so that you don't lose all of the energy that you put into conditioning the air in your house.

They're a little spendy in the $1,000 range, but if your issue is the inside air is too humid and moisture is building up on the walls and windows, it's a good system to use for comfort.

You can also get a whole house humidifier / dehumidifier set for roughly the same price, but that doesn't provide fresh air for your house so I would only suggest that if your air cannot maintain the 30-50% humidity levels that are most comfortable for you with the ERV/HRV system.

They described having an HRV: "it has an outside air circulating system fitted with a heat exchanger."

That's what "an outside air circulating system fitted with a heat exchanger" is.

Open fireplaces suck a huge amount of air from the room. It was once explained to me that in one particular case (a specific house) the open fireplace would typically suck 150 cubic meters of air every hour, when that was replaced with a wood stove it went down to 15 cubic meters/hour. So, an order of magnitude of difference. Those numbers shouldn't be taken as accurate of course, but at least that house got much warmer simply because they didn't have all that air sucked in from outside all winter.

Those much reviled Insulate Britain folks might have been on to something after all.

Insulation in itself can cause more problems than it solves in some circumstances though, especially when it results in moisture becoming trapped within the fabric of the building.

Cavity wall insulation is one such example where there was a mad splurge of works being done poorly and where inappropriate, the inevitable result being further works required to remove it and make good the damage caused.

Insulate Britain's dream come true would be much more of the same.

> Cavity wall insulation is one such example where there was a mad splurge of works being done poorly and where inappropriate, the inevitable result being further works required to remove it and make good the damage caused

That's called incompetence. Thats what happens when you seal a house that has no mechsnical ventillation.

incompetence us rampant in the construction industry here.

I live in a newbuild, this year communal heating system has burst, and flooded 13th floor with boiling water. Mulpiple residents ended up in the hospital. Where was spectacylar a 50 meter waterfall from the side of the building.

You know why? They used rubber pipes, and they weren't rated to habdle the temperature.

I don't think anyone had an issue with their message - just their method.

If every social movement was always polite and nice with our methods, we'd still be slaving for the lord and dying for the king.

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