Add supplemental heat to conditioned crawlspace
I built a 300 sq ft addition this summer on top of a fairly shallow (24″) ICF crawlspace. This is in the middle of Canada, and now that winter has set in im starting to see how the heating system functions.
我将两个单独的分支从强制的气炉延伸到加法中，并根据空气流和空气变化的说明在每个分支的远端打开一个小孔。从爬行空间进入现有地下室以进行回流空气，有一种公开通道的方式。
The addition itself stays close to the the temperature of my main house, perhaps a degree or two cooler (19 C), but the crawlspace is approximately 5-6 degrees Celcius cooler than the house (15 C). This obviously creates a cool, unpleasant floor and results in the addition feeling even cooler than it is.
我需要提高爬网空间中的温度，而不会从添加本身中吸收更多的空气。我的第一个测试是在爬网空间内的管道中增加一些孔，但我不想做太多的孔，以至于添加变得更冷。
如果我选择在爬网空间中添加补充电加热器，我最好的选择是什么？
I was thinking that a simple baseboard heater, suspended close to the crawlspace floor might be my best bet? Im a little concerned though about whether or not two feet of head room above a baseboard is enough.
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Replies
A heater with a fan might be better - less localized heating above it. If your other heat source isn't electric resistance, then I'd try hard to use it for the crawlspace (for efficiency reasons). For example, add a booster fan to your branch ducts to move more CFM, making more available for the crawlspace.
您可能需要考虑在爬网空间中添加过热迷你拆分。与电加热器或让您的HVAC家伙建立爬网空间的运行费用约为1/3。作为具有恒温器的自己的区域。
您是否正在监视爬网空间中的湿度？如果是这样，那是什么？
Walta
If the crawlspace is that much cooler than the house even with some supplied conditioned air, there is a good chance that there are cold air leaks. Warm air in the house naturally rises, and it tends to pull cold air in through penetrations into the crawl space. Check carefully for air leaks, and seal all of them you find. This can make a big difference in crawl space temperatures.
DJ,
如果您最终选择了电动底板加热器，那么大多数制造商都希望上面有12英寸的间隙。
You want to consider a very small minisplit here. Electric resistance heat is usually one of the most expensive ways to heat a space. If you do want to go with electric resistance heat, a heater floor system with a bit of insulation underneath might be a more efficient option. Heating a crawlspace just to make the floor above warm seems pretty wasteful to me.
I’d also look to be sure that the crawl space is properly air sealed and insulated and fix that first. Any type of heat you put into the crawlspace is of limited use if you have big air leaks or uninsulated walls.
Bill
>"You want to consider a very small minisplit here."
No, you don't. That's beyond silly, edging into "ludicrous" territory here.
甚至一个叫三菱将极其机汇的ersized & inefficient for the design heating load of an attached 300 square foot addition's crawlspace, and wouldn't be efficient enough to come anywhere near "paying off" either the environmental or financial cost of the mini-split. You'd be better off spending the money on grid-attached solar.
>"If you do want to go with electric resistance heat, a heater floor system with a bit of insulation underneath might be a more efficient option. "
YES!!!
电动网型辐射地板在地板恒温器（不是R19左右）的地板恒温器（不是室内恒温器）上运行，除非将地板温度升高到它变成的点，否房间的主要热源。15c楼层使19c房间感到寒冷，20℃的楼层将在19C 300平方英尺的房间中增加约1000 BTU/HR（〜320瓦）。这产生了舒适性的巨大变化，但仍然没有一些人在寻找的“舒适的脚趾”辐射地板。它在每个度C的每个度数上都爬上1000 BTU/HR，高于平均室温，因此，不得将其提高并使其成为房间的主要热源是一分钱的。
>"... look to be sure that the crawl space is properly air sealed and insulated and fix that first. "
绝对没错！！
Even with the stemwalls well sealed and insulated the crawlspace the floor temp will run roughly ~18C or a bit less in a 19C room, and the crawlspace air temp will be roughly midway between 18C and the subsoil temperature, which in parts of the lower Canadian midwest can still be about 5C. A location decribed as "... middle of Canada..." could be even colder than that, depending on how that middle is measured. Centre of Canada Park (a bit east and slightly south of Winnipeg) is one thing, the true geographical "...middle of Canada..." would be much colder, near the border between Nunavut & Manitoba.
Given that the humidity in both the house and crawlspace should be the same, as they are supplied by the same forced air (maybe that's not a good assumption?), is there any danger that the much cooler crawlspace will accumulate moisture?
>“鉴于房屋和爬网空间的湿度都应该是相同的，因为它们是由相同的强制空气提供的（也许这不是一个好的假设吗？），是否有危险，凉爽的爬网空间会积聚水分？”
Not really, unless there is substantial, active humidification of the conditioned space air going on. In most midwestern Canadian homes the wintertime indoor air's dew point would be no higher than ~5C, the dew point of 21C/35% RH air. Only in summer would the conditioned space air's dew point be substantially above the temperature of the crawlspace floor, but the crawlspace is being delivered air-conditioned air (not merely ventilation air) it will have a similarly low dew point.
The deep subsoil temps in Winnipeg are still north of 5C, the southern border of Nunavut, not so much. So it really matters which "...middle of Canada..." location we're discussing. In permafrost territory it's probably worth insulating the crawlspace floor.
I am in fact in Winnipeg, so not exactly the middle of Canada, but definitely cold enough. Its been -20 to -30 C with the windchill this past week and my crawlspace is hanging out around 14 C, with the room above about 19 C. Humidity in the house is about 35 % while in the crawlspace its about 45%. I think thats too be expected as most of the lumber down there will still be drying somewhat.
p的狭小空隙本身erfectly sealed, I was meticulous with a 10 mil vapor barrier, on the ICF walls up to the 4" of ridgid foam in the joist bays, all gaps foamed or caulked. The sump pit is sealed as well as I could, but there may be a small leak around the hole for the discharge pipe.
我很想打开爬网空间中的HVAC管之一，以使更多的热量进入该区域。如果上方的小房间（泥房）从中窃取热空气的温度很大，我可以在其中的墙壁空间加热器中添加一个小的强制空气电气。我认为，将爬网空间达到18至20度将有很长的路要走，使其上方的房间保持更舒适。
I think Id rather have a little electric heat in an occupied area where it will be seen rather than tucked away in the crawlspace anyways.
>"...my crawlspace is hanging out around 14 C, with the room above about 19 C. Humidity in the house is about 35 % while in the crawlspace its about 45%. I think thats too be expected ..."
The dew point (a meausure of absolute humidity) of 19C / 35% RH air is 3.2C. Cooling off that same body of air to 14C would yield an RH of 48 %. So the air in the crawlspace is at about the same humidity level as in the room above.
>"The crawlspace itself it perfectly sealed, I was meticulous with a 10 mil vapor barrier, on the ICF walls up to the 4" of ridgid foam in the joist bays, all gaps foamed or caulked."
您是否在整个地板下面有4英寸的泡沫切割，还是在ICF茎墙顶部的乐队托梁上说话？
>"Im tempted to open one of the HVAC ducts in the crawlspace considerably more to get more heat into the area. "
That will do it. Be sure there is an adequate return path commensurate with the supply too, even if you have to cut in a floor grille somewhere. Simply pressurizing the crawl space with just a supply duct will depressurize the rest of the house relative to the outdoors.
我要假设现有的炉使用了一种合理的成本效益的加热方法，并且适当尺寸以加热房屋，增加和爬网空间。如果是这样，您不需要其他热源。全停止。
您需要在爬网空间中更多的热量，这意味着更多的空气进入爬行空间。您不会谈论分区。如果现有系统未分类，或者添加是大区域的一部分，则意味着平衡流量。有没有从爬行空间返回空气的路径？没有空气出来。除此之外，您还需要在爬网空间中更大的开口，以使其获得更多的空气。这并不一定意味着房屋的其余部分会很冷。恒温器将保持温度，这意味着炉子的运行时间更长 - 但是请记住，热点是舒适的。一旦您在爬网空间中添加了管道和返回路径并将其达到所需的温度，那么如果房屋的一部分在温度上大不相同，则可以处理平衡。可以使用减震器，助推器或分区来实现平衡。 But don't assume it's necessary, it would only be necessary if part of the ductwork is dramatically mis-sized.