Mini split heat for an 1880 remodel
Hi, I’m new here but I’ve been reading these Q&As extensively in trying to plan a heating system for my home. We are currently working on a large remodel of the house and I’ve been delaying the HVAC because I wasn’t able to get any reasonable quotes for installation.
The house is ~1550sqft with a full basement (unfinished), main floor of about 950sqft, and upstairs of about 600sqft. Upstairs is currently 3 small bedrooms, master is 170sqft, secondary BR is about 150sqft and the third BR is about 140sqft. We are planning to open up the third room into an upstairs lounge area connected to the stairway/upstairs landing bringing it to around 170sqft. with no door. Next to that room is an unfinished attic space that is on the same floor as the upstairs bedrooms. That area will eventually become a bathroom of roughly 100sqft with sloped ceilings. Above the current bedrooms is another unfinished attic which is currently loosely insulated, plans to improve the insulation up there and maybe do something fun with it at some point.
The existing heat is an oil furnace in the basement ducted to the first floor but no ducts running to the second story. The house is in southern VT and this past winter we were able to keep the heat at about 62º and ran through about 800 gallons of oil between Christmas and now (end of April). Not very comfortable but I really hate oil and we were working on the house most days.
墙壁上没有隔热材料，我不打算添加任何隔热材料。房子的气球框起来是灰泥和板条，除了一个没有墙壁的房间。我在这些墙壁上添加了R-15矿物羊毛，并用5/8的干墙完成。在某个时候，我计划将地下室中的门槛隔离，以稍微改善墙壁。
The house gets great southern exposure and warms up quite a bit when the sun comes out. The temperature is also holds fairly steady after sunset and starts to get colder about 2 hours later.
I hope that’s enough info, let me know if more is necessary. I’d really like to get a heating system (cooling is less important) that runs on electricity. I’d like heat pumps/mini splits so that: 1. no more oil 2. potential for solar 3. chimney is in rough shape and needs to be removed or rebuilt.
I had a couple installers come out and quote the job, the lowest price I got for the full house was ~$25k for ductless splits in every room. The other most reasonable contractor was willing to let me do the electric and only install splits for nearly all the rooms for ~$15k. This would leave only one bedroom without a heat source, the upstairs lounge area being heated ambiently by the adjacent bedroom, and one central room downstairs also being heated ambiently. Not a terrible setup but the units in the small bedrooms seemed hugely oversized. 9k each for less than 200sqft.
This lead me to researching and designing a system myself. Eventually I settled on a small ducted unit upstairs installed in a corner at the upstairs landing that shares walls with the master BR and second BR. The idea here is that it would heat with vents straight through those walls to the two rooms and a large return up above in the “hallway”. A third vent would point towards the upstairs lounge room. Those two BR’s would have transfer grilles above the doors for when the doors are closed and probably one supply each run straight through the wall. Is this crazy? Do people do this sort of setup? I can’t seem to find examples, but I’m thinking a 12k Fujitsu would do the trick here.
其次，我愿意对楼下的想法。房间很大，大部分时间都足够开放，可以使用无管墙单元，但是我们还可以选择使用现有的地板寄存器并在地下室做一些管道。
I’d love to hear thoughts and ideas and I will happily send some floor plans if people think it would be helpful.
为长期的帖子道歉，并期待与大家交谈！
GBA Detail Library
由气候和房屋部分组织的一千个建筑细节的集合
答复
我是一个迷你小伙子，但老实说，我不确定它们是否会成为您应用程序的正确解决方案。您不希望每个房间都有迷你拆分头。我以艰难的方式了解了这一点 - 它将短期循环，并且通常超大，导致高电费和不舒服的房间。
IMO，在您的应用程序中使用迷你切片的唯一方法是悬浮空气密封。在阁楼和爬行空间中用火块盖住墙壁开口。密封您能想到的每一种穿透。当房屋被正确密封时，迷你拆分条件空气将留在信封内，您不必尝试在每个房间里挤压头部。
You said you don't intend to insulate, so I'm assuming you wouldn't want to undertake the air sealing project either. If you want electric heat, but floor mounted baseboard heaters. They're cheap and effective - I've heated homes as old as yours with them before.
我看到这所房子的方式并不是因为它建造得很好，而是相反。您的旧墙壁被当今的标准闪烁，因此大量的水进入了您的墙壁，只要水蒸发并在事情变烂和发霉之前就可以从墙壁上运出。谢天谢地，您没有任何隔热材料和大量的空气通过墙壁移动。如果您停止空气或越过墙壁移动，这是一个平衡的系统，事情可能会变得丑陋。
除非你准备再引燃墙壁insulating and air sealing is a very risky proposition.
Until you are ready to redo the flashing you can’t insulate and air seal and install modern heating. As it stands you current heat load is just so unimaginably large throwing oil at the problem seems like the only answer.
Walta
感谢您到目前为止的回复，只是为了澄清我真的没有计划绝对绝缘的墙壁，超出了一个房间已经完成的工作。我打算做的进一步的绝缘层将在窗台上的阁楼和地下室。
As a thought experiment let’s imagine that the oil fired furnace is either completely broken down or nonexistent. Is there something else that is recommended for a house like this? I’m *really* not interested in heating with oil and additionally there are looming problems with the current setup that I may have mentioned briefly (chimney issues, nonexistent ducting upstairs, oil tank installation problem).
是否有任何理由不使用管道的热泵？
感谢大家到目前为止的意见和答复，让我知道您是否需要其他信息。
First you need to know how many BTUs will be required to heat this building.
如果您具有准确的油填充数据与当地天气数据相结合，则可以生成非常准确的热负荷号。
If that is not possible you will need a manual J calculation.
鉴于您缺乏隔热材料并猜测您有单窗格的窗户，如果您需要大量设备来获得-15°，我就不会感到惊讶
注意，每吨设备需要每分钟移动400立方英尺的空气，它可能会感觉更像是风洞，而不是房屋。
Walta
>“如果您具有准确的油填充数据与当地天气数据相结合，则可以生成非常准确的热负荷号。”
Details on how to go about that are spelled out here:
//m.etiketa4.com/article/out-with-with-the-----in--in-with-the-new
If it's only going through 800 gallons per heating season you won't need more than 3.5-4 tons of cold-climate heat pump to cover the load at design temp. In my area that would run about $13-16K in competitive bidding if all ductless. That is explicitly NOT going to be a "ductless head in every room" solution. In most cases it will make more sense to use at least a couple of ducted cassettes serving multiple rooms as a single zone.
即使您不打算将墙壁隔离（某些古董壁堆积可能会冒险），仍然值得一轮打击器门和IR成像定向空气密封。尤其值得隔热和空气密封未完成的地下室墙，即使不将其用作居住空间，这是低风险/高奖励。
凭借漏水的地下室和漏水的阁楼，24/7的堆栈效应渗透是很大的，导致一楼冷的地板和干燥的冬季室内空气。密封阁楼和地下室都可以舒适地产生戏剧性的上升，即使不隔离框架的墙壁。它还降低了地下室任何管道的冻结风险，以及地下室中任何未绝缘管道的分布损失。
I have a 1901 house with an unfinished basement and did a ton of air sealing as well as putting mineral wool in the rim joists. I think it helped a lot. I am honestly not sure whether there is insulation in the walls of the older part of the house (some of which were taken down to the studs during a major remodel/addition about fifteen years ago). One bedroom wasn't touched in the remodel and is still quite chilly. At some point we will likely take the walls out there (there's a dropped ceiling that should go, and we suspect not great wiring behind it, based on what we found in other rooms) and I would like to put mineral wool in then (possibly even on the inside wall, for soundproofing). But we haven't got any plaster walls remaining.