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Have we forgotten to make heat traps? (2012)

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Re: Have we forgotten to make heat traps? (2012)

#31

Post by SECProto »

781 wrote: post #23
kragen wrote: post #22

Earlier quoted context omitted.

Wouldn't it be better to make the heat trap itself with 45 cm or less of copper, then hook up the PEX to its output? Copper will last centuries in continuous contact with hot water, but I'm not sure PEX will.

I'm pretty sure a house is not expected to run centuries from now with present day electrical/piping systems. It's a bit like people from 200 years ago debating what to make the candle holder from so that it lasts 100 years.

My parents house is hot water heated. Originally was coal fired, then oil, then a replacement oil heater, now electric. All the pipes and radiators are original. It's 115 years old.

The whole house is built (and maintained) with a different mindset.

(I think they removed the last knob-and-tube light socket a couple years ago)

Re: Have we forgotten to make heat traps? (2012)

#32

Post by jessaustin »

egypturnash wrote: post #29
jetbooster wrote: post #9

Earlier quoted context omitted.

That's interesting, as Hydronic heating is the standard heating method over here in the UK. Reason its not done in the US I image is we don't often ever need AC, so we only need to be able to turn the temp up.

You’ve never been to the Southwest or the Gulf South, have you? There are parts of the US where you would die without AC. Seriously, like when you get a brownout on a hot summer day in New Orleans or Santa Fe or Dallas, people start dying. Mostly the elderly and kids.

GP is in UK, and specifically allowed for the difference between that situation and situations in USA. Nobody wants your grandma to die.

Also, the heat in Santa Fe is much different than that in New Orleans.

Re: Have we forgotten to make heat traps? (2012)

#33

Post by foobarian »

Declanomous wrote: post #15
tomkinstinch wrote: post #13

Earlier quoted context omitted.

Hot water "hydronic" heating with radiators is very common in the US as well, at least among homes in the Northeastern US constructed before the 1960s. It's a shame more new construction does not use hot water heating in conjunction with central air for cooling because radiators are much quieter, more efficient, and better for those with asthma.

I live in a house with steam heat. Steam systems often get converted to hot water, but in general I have a few observations related to radiated heat. 1) Steam and other radiant systems don't deal with temperature setbacks well. They take FOREVER to warm up a house after a set back, so don't bother with a deep setback overnight, and if you are gonna turn down the heat because you are going to be gone for a while, expe…

> you can upgrade a forced-air system to use better filters, which basically gives you a filter for your entire house.

This is a reason I really like our forced air system (New England house from the 50s): it can circulate and filter the air even without heating or cooling it. I have it run hourly for part of the day and it does wonders to keep the air fresh (i.e. we really notice when the system is off for some reason).

Re: Have we forgotten to make heat traps? (2012)

#34

Post by inflatableDodo »

gxx wrote: post #19
LeoPanthera wrote: post #12

Earlier quoted context omitted.

UK hydronic systems usually use radiators. US systems are almost always under-floor.

I once had a new house with hydronic under floor heating - the worst heating setup I've every had - horribly slow to respond and expensive to operate. We turn down the heat to sleep and finally I just shut off the heat to the bedrooms and heated them a different way. Our initial experience with the system was even worse than it might have been. The people who installed it including the thermostats were plumbers and d…

Electric underfloor heating works pretty well. Though personally I think we should all go back to having hypocausts.

Re: Have we forgotten to make heat traps? (2012)

#35

Post by kragen »

781 wrote: post #23
kragen wrote: post #22

Earlier quoted context omitted.

Wouldn't it be better to make the heat trap itself with 45 cm or less of copper, then hook up the PEX to its output? Copper will last centuries in continuous contact with hot water, but I'm not sure PEX will.

I'm pretty sure a house is not expected to run centuries from now with present day electrical/piping systems. It's a bit like people from 200 years ago debating what to make the candle holder from so that it lasts 100 years.

There are a lot of cases where piping problems have totaled houses. A substantial fraction of houses built with polybutylene piping have already been demolished because of it.

My concern is not so much that a sample of 100 PEX heat traps installed today will all burst on the same day in 2059 or 2159. It's more that if the average lifetime of PEX under those circumstances is only, say, 50 years, maybe there will be a few percent that burst in 5 or 10 years, depending on how variable the corrosion rate is. So if you can protect yourself from that with 45 centimeters of copper, which will cost a heck of a lot less than the water heater does, maybe you should.

Re: Have we forgotten to make heat traps? (2012)

#37

Post by Retric »

Declanomous wrote: post #24
Scoundreller wrote: post #21

Earlier quoted context omitted.

> They take FOREVER to warm up a house after a set back, so don't bother with a deep setback overnight This is incredibly true in intermittently occupied areas. Just heating the air is one thing. Heating everything around it just to get warm is another. If you're in a private/semi-private office 9-5, having your own heater or window A/C gives you a lot of control and is incredibly efficient since you can turn it on/o…

Yeah, exactly. I like to have it relatively cold at night, so with forced air I set the heat to come on about 15-20 minutes before I want to get out of bed, and turn off 15 minutes after I leave for the day. With radiant heat, if I want it to be 55 while I'm sleeping, and 70 when I leave my bed, my heat will come on 2 hours before I'm going to get up, and the temperature will slowly increase over that time, leading t…

Significantly overshooting the temp is something you can avoid. The thermostat needs more information, but predicting the temperature in 10 minutes if the heat is turned off now is not that complex.

Ex1: https://www.heat-timer.com/steam-outdoor-reset-2/ Ex2: https://nest.com/support/article/What-is-True-Radiant#how-it...

Re: Have we forgotten to make heat traps? (2012)

#38

Post by misnome »

NeedMoreTea wrote: post #25
jetbooster wrote: post #9

Earlier quoted context omitted.

That's interesting, as Hydronic heating is the standard heating method over here in the UK. Reason its not done in the US I image is we don't often ever need AC, so we only need to be able to turn the temp up.

Forced air was very briefly in in the UK. For a few - maybe as few as five - years around the early or mid 60s forced air was fairly commonly seen in new build houses and the type of small blocks that have 6 or 8 flats. By the seventies no one was putting them in new builds any more, and people were already ripping them out - or sealing up the vents - to go back to just a fire - though without a chimney it would have…

We lived in a house with this under-floor-air system until we moved last year. We inherited it from my mother-in-law a few years previously. She didn't really think of maintenance, and so turns out it was using the original gas heater system.

This was quickly condemned when we got it inspected - it had a crack in the heat exchanger and - these things were apparently only designed to last 25 years. Lasting 50 was pretty impressive/dangerous.

You can get replacement heaters for them, but it's pretty niche, needs to be imported from Europe, and because of the age normally involves dealing with asbestos insulation. It's also apparently virtually impossible to get the venting cleaned, as it's embedded in the flooring (under concrete for the group floor). (Edit: And this caused real problems for Asthma sufferers)

While it worked though it was pretty good, it heated rooms extremely quickly.

Re: Have we forgotten to make heat traps? (2012)

#39

Post by codfrantic »

jetbooster wrote: post #9
mcmatterson wrote: post #4

I designed and installed a complete hydronic heating system in our house last year, replacing a conventional forced air system. It being the first time I'd ever done such a thing (and indeed, the first time I'd ever really been exposed to hydronic heating at all) I learned everything through reading (mostly the excellent idonrics series at https://www.caleffi.com/usa/en-us/technical-magazine ). I went really deep on…

That's interesting, as Hydronic heating is the standard heating method over here in the UK. Reason its not done in the US I image is we don't often ever need AC, so we only need to be able to turn the temp up.

I was really curious to read about this type of heating, then I read your comment. Quickly imagegoogled the term and found that this is the standard in most of north/west Europe.

Re: Have we forgotten to make heat traps? (2012)

#40

Post by Moru »

m463 wrote: post #30
gxx wrote: post #19

Earlier quoted context omitted.

I once had a new house with hydronic under floor heating - the worst heating setup I've every had - horribly slow to respond and expensive to operate. We turn down the heat to sleep and finally I just shut off the heat to the bedrooms and heated them a different way. Our initial experience with the system was even worse than it might have been. The people who installed it including the thermostats were plumbers and d…

I wonder if better PID tuning would help, maybe adding stuff like ambient outside temperature or weather prediction as a system input. I know the nest thermostat does a lot of systemic learning and understands the outside temperature. (I'm not recommending that system, just that a little modern control theory might make things workable)

I thought all heating systems had outdoor input for temperature. I know all houses I have lived in has had that the last 40 years at least. But I live in a cold area so I guess that's different. -38 C is uncommon but happens now and then. Also the isolation of the houses are better and that also helps with leveling out temperature differences.
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