g*****9
发帖数: 4125 | 1
Depends on your local area unit cost. Some area electricity is less at night.
Baseboard heating is 100% efficient, that means 100% of the electrical
energy will turn into heat to heat up your home.
No gas furnace can be 100% efficient, that mean not 100% of the engergy in
gas can turn into heat to heat up your house. |
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a***s
发帖数: 143 | 2 【 以下文字转载自 Georgia 讨论区 】
发信人: autus (虹), 信区: Georgia
标 题: 有人知道aux heat和emer heat的区别吗？
发信站: BBS 未名空间站 (Tue Oct 5 10:51:32 2010, 美东)
天冷了，准备开暖气，发现有两种，aux heat和emer heat，不知道有什么区别，哪个
省钱阿 |
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t**d
发帖数: 6474 | 3 heat pump如果室外低于30F的时候，会启动电阻丝加热，耗电量是惊人的。一般heat
pump要跟gas 炉子一起用。当室外50度以上时，用heat pump，室外低于40度，烧气。
你可以算一下烧气还是用heat pump合算。目前气很便宜，heat pump即使在室外50度的
时候（效率是可以到300%）也不一定合算。 |
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b******o
发帖数: 125 | 4 Forced Air, Heat Pump,Floor Furnace
同一个小区的townhouse，有的在Heating同时有Forced Air, Heat Pump
有的只有 Heat Pump
有的是Floor Furnace, Forced Air
到底有什么区别？哪个值钱点？或者哪个省能源？ |
|
z****e
发帖数: 555 | 5 I am thinking to withdraw the offer.
If you convert this heating bill to 30-year mortgage, for extra $2000
heating bill, it is = $33,000. That is a lot money.
If it is a gas heating house (1954 sqrt), I bet $1600 per year heating will
make the house comfortable.
yes I am in ma. The problem is that there is no house on market. :-(
heat. |
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N**s
发帖数: 1916 | 6 My guess: 楼上的是heat pump only, electrical.basement unit is more likely
hybrid: heat pump works when outside is relatively mild, and gas kicks in
when outside is cold to an extent heat pump heating is not efficient.
heat |
|
i****e
发帖数: 289 | 7 昨晚开始天突然很冷，5－20F大概，今早醒来觉得冷，发现室内才62F，T-Stat显示
auxiliary heat on（这个以前没注意过开过没），以为是heat pump在defrost什么的
，可是都5个小时了还是徘徊在63－64F，我调到80F了也还是这么高不肯升，出去看了
一下heat pump内外好象肉眼看不到
结冰呀，就一直响着不停大风扇也是还在转，然后furnace好象不停的run，但是vent不
排风出来，只是把手放在vent口才感觉到是热的。
是heat pump坏了吗？还是天太冷了heat pump不加热呀？
谢谢 |
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S*A
发帖数: 7142 | 8 就是说，你的 Heat Pump 的温度控制在检查的时候是
放在 EM 的位置。然后后面的是 FYI， 如果 Heat Pump
只有放在 EM 位置才能加热房间说明 Heat Pump 有故障
需要维修，否则浪费很多能源。
但是 Inspection 没有说你的 Heat Pump 是不是需要放在 EM
才能加热，只是说检查的时候发现 Heat Pump 是在 EM 上。
这个检查他们没有做，只是提到如果必须 EM 才能加热就要
去维修，他们当时没有时间或者没有条件（房间本来温度就高？）
做这个检查。 |
|
y*****g
发帖数: 521 | 9 房子已经买了。这一项没在inspection report的summary里，所以今天有空才看到。。
。卖家当时请人修了summary里关于hvac的几项，我列在这里，大牛们给看看：
21.Central heating and cooling systems were operated, temperature
differences were recorded in the main body of this report and the systems
were run until at least a 3-5 degree change was noted on the controlling
system's thermostat. Emergency heat positions of thermostats if available
were tested. Covers and access panels were not removed. The heating and
cooling systems should be tested, inspected and s... 阅读全帖 |
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h********o
发帖数: 3320 | 10 heat pump只是在不是太冷的地区用比较划算，但是在南加州这种不冷的地方，heat
pump远远没有gas furnace流行，其中原因可能和南加州电费比气贵有关。 另外，heat
pump的效率没有gas furnace快，吹出来的风如果你用手试探没有感觉很热，就是说
heat pump是很温和的缓慢升温，用起来的效果没有gas furnace舒服。 我原来用的是
heat pump，现在是gas furnace。 |
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a***2
发帖数: 24 | 11 新买的房子，2楼和3楼是共用heat pump，大概2000多sfts。发现出风口的风几乎没有
，尤其是某些卧室。但是机器是运作的。
请了技师上门检测，他开始认为需要清洁coil，但是发现里面其实不脏。他认为是air
handler功率不足及air duct太细，然后建议我们换整个heat pump系统，并且换一个更
大的air duct。
heat pump推荐型号： carrier infinity 20seer 3tons
air duct 16X8
报价 13000
现在的问题是
1 更换heat pump，是否能解决出风过小及不均匀问题
2 该类型机器效果如何，价格是否合理
我们原来heat pump是concord 13seer 3tons 4HP13，年代不清
多谢大家！ |
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s****e
发帖数: 720 | 12 刚刚搬进新房，请教一下大牛如何改善二楼的heating：二楼有个furnace
给二楼单独供暖，二楼有四个bedroom，最小的bedroom很小，但和主卧一样，
有自己独立的卫生间和walk in closet。根据vent的温度和风速，这个小卧室
应该是heating loop的起点，而主卧是终点，但主卧的面积比几乎是小卧室的
两倍，Thermostat在主卧。
现在的问题是加热非常不均匀，heater开了后，主卧和卫生间的温度差别估计
快到10度了，另外两个卧室的温度，一个接近小卧室，一个接近主卧。小卧室
以及它的卫生间、closet各有一个vent，我试着把这三个vent都关了,情况有改
善，但小卧室还是会比主卧热个4到5度。由于热风很强劲。这三个vent虽然关了
还是会感到很强的热风。觉得从这三个关了的vent出来的热风都要被主卧vent
出来的热风强劲。我也试着把另外一个卧室的vent也彻底关了，但发现即使这样
对主卧vent风速的影响基本没有。所以两个比较热的卧室即使vent彻底关上，
热空气还是blow out，温度总体也还是要比另外两个卧室高。
其实设计的时候他们应该... 阅读全帖 |
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C**K
发帖数: 3672 | 13 租房最好找包heat的, 沒包的話, gas heat會比燒油的省錢. 兩百sqft差別不大, 主要
是看房子的insulation--基本上不會很好, Boston房子普遍老舊.
heat一般要開半年, winter非常長, heat老是開開關關不是辦法. 板上怕冷的開七八個
月的都有. 不是開玩笑的, 否則不是水管結凍就是幼兒生病, 水管結凍的後果很慘. 有
的人想省錢, 回國時把heat調太低, 房子淹水. |
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h********5
发帖数: 386 | 14 Most small companies don't offer fixed price plan due to financial resources
and risk management.
As required by law, once a customer signup a fixed price plan the dealer
MUST buy certain amount from his supplier to prevent potential default due
to sharp price spike. That will tie up some capital for smaller companies.
Some even ask their customer to pay in full upfront when signup for fixed
plan or charging an enrollment fee. Others go to future market to hedge
their price risk which adds to th... 阅读全帖 |
|
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c****8
发帖数: 407 | 16 - Depending on the system you want to replace with. There is a Chinese ads
about getting government supplement for replacing with some energy saving
model. I used them for replacing my central air with heat pump which total
cost is around 13k, but I paid around 5k only. My home uses water heat, and
the heat pump is kind of a backup heat source in my home, good for months
that is not that cold. If you have force air, i guess it won't cost you too
much to add a Furnace there.
- If your heat only h... 阅读全帖 |
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d*********g
发帖数: 225 | 17 大家有没有用过heat Pump，那种heat and cool一体机？
不知道电费和gas比如何？
费用差不多的话，就把家里用gas heat的换成heat pump了
实在是没找到有gas heat，带cool，through wall的那种空调 |
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b***e
发帖数: 4591 | 18 ☆─────────────────────────────────────☆
lybh (芊芊~~Claire) 于 (Tue Dec 16 14:33:49 2008) 提到:
新换了furnace，结果那个contractor搞不定heat pump和furnace同时连到honeywell的
thermostat上。ft……
不想放弃heat pump,所以想另找technician帮忙。
有经验的麻烦推荐下吧！
☆─────────────────────────────────────☆
raye (sleepypig) 于 (Tue Dec 16 15:13:55 2008) 提到:
wk~有钱宁，又是furnace又是heat pump的~~
不过你找的这家公司也太有创意了～～都连到一起，省下来一个别的也用不着啊～～
偶嚼着这大房子还是用heat pump省钱，初期投资几年电费就还回来了（前提是通风管
道不用你装，这个通常比heat pump itself贵很多），剩下十几年就是纯赚的。
我知道一家不错的，他们做commercial多，residen |
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l*****9
发帖数: 9501 | 19 Jeremy Lin Helps Miami Heat Win Big
This is a follow-up to my story about Jeremy Lin’s effects on the price of
Knicks tickets, both home and away.
Lin and the Knicks will be going for their sixth straight win when they play
the Raptors tonight in Toronto. The game is expected to be sold out – only
the third game that the Raptors have sold out this season – thanks in
large part to Lin’s presence.
The Knicks return to New York tomorrow to begin a five game homestand, and
their next away game isn’t... 阅读全帖 |
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L*********r
发帖数: 1201 | 20 ☆─────────────────────────────────────☆
biplane (双翼机) 于 (Wed Oct 22 19:47:20 2008) 提到:
正常起落程序没问题。
问题在于两种情况：go around 和 touch and go.
POH 写的不太清楚，落地以前 Carb Heat是打开的，如果是需要全功率复飞/起飞，啥
时候关闭Carb Heat？
我的理解是先把油门推到底，襟翼20度(Cessna 152/172)，再关。
开Carb Heat会损失一点功率，但是有关它的时间，不如先推油门，尤其是在遇到紧急
情况的时候。其次是如果襟翼放在30度，阻力太大，飞机几乎没法爬升，这点我有体会
。最后再关闭Carb Heat，挤出发动机最后剩余的功率。
不知道这么理解有没有问题，欢迎大家讨论一下。
☆─────────────────────────────────────☆
trajan (笨) 于 (Wed Oct 22 23:12:16 2008) 提到:
我两年以来一直飞fuel-injection的，所以对carb heat |
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m**l
发帖数: 15 | 21 【 以下文字转载自 JobHunting 讨论区 】
发信人: merl (merl), 信区: JobHunting
标 题: Internship: Radiative heat transfer
关键字: intern
发信站: BBS 未名空间站 (Thu Feb 23 17:02:47 2017, 美东)
MERL is looking for a qualified intern to conduct research in radiative heat
transfer. A solid background in theoretical understanding of heat transfer,
solid state physics, and electromagnetic fields is expected. Research
experiences related to thermal radiation and energy conversion are required.
Expertise in numerical modeling and simu... 阅读全帖 |
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a***n
发帖数: 578 | 22 Taking the heat off: Nanofluids promise efficient heat transfer
by Chad Boutin
Heat transfer is not the most frequent topic of domestic conversation. But if,
on a 90-degree day, your air conditioner breaks down or your car radiator
boils over, it is immediately clear how critical it is to move heat
efficiently from one place to another.
Steve Choi (left) and Jeff Eastman are working with industry to improve the
understanding of nanofluids.
Engineers have been working for decades to develop more |
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n****t
发帖数: 729 | 23 You said: "Electricity --> thermal (100%, or > 100% by heat pump)"
Your statement about the heat pump is very misleading.
The extra amount of thermal energy that makes seeming >100% efficiency comes
from the thermal energy transferred by the heat pump from the cold side to
the hot side of the heat pump. It is not the thermal energy transformed by
the heat pump from electrical enery.
Energy can be transferred from one object to another, or transformed from
one form to another, but can never be cr |
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m**l
发帖数: 15 | 24 【 以下文字转载自 JobHunting 讨论区 】
发信人: merl (merl), 信区: JobHunting
标 题: Internship: Radiative heat transfer
关键字: intern
发信站: BBS 未名空间站 (Thu Feb 23 17:02:47 2017, 美东)
MERL is looking for a qualified intern to conduct research in radiative heat
transfer. A solid background in theoretical understanding of heat transfer,
solid state physics, and electromagnetic fields is expected. Research
experiences related to thermal radiation and energy conversion are required.
Expertise in numerical modeling and simu... 阅读全帖 |
|
h****o
发帖数: 49 | 25 I found that heat capacity=density*specific heat, then since
the density
has the unit of kg/m3, specific heat is J/kgk, then heat
capacity should
have the unit of J/m3k, right? (Holman, heat transfer, the
last
paragragh of page 4)
thermal expansion coefficient has the unit of ppm-k;
ppm=parts per million, who can find some explantion about
ppm? I can not understand it.
Thx. |
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h****o
发帖数: 49 | 26 is ppm so small? I am sure.
is specific heat=specific heat capacity?
because some books regard heat capacity and heat specific
have the the same unit, that's J/kg*k, I was confused. I
think "specific" should not have unit, usually defined as
the ratio of something to that of wate. e.g., specific heat
is defined as :
The ratio of thermal energy required to raise the
temperature of a body 1c to the thermal energy required to
raise an equal mass of water 1c.
But here it has the unit of J/kg*k, real |
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w*******y
发帖数: 60932 | 27 Sunbeam Fleece Heated Electric Warming Blanket:
http://www.walmart.com/ip/Sunbeam-Fleece-Electric-Blanket-Seash
Get cozy this winter with the added warmth of the Sunbeam Fleece Electric
Blanket. Ten heat settings add to the functionality of this electric warming
blanket. The soft fleece keeps you comfortable throughout the night while
the adjustable heating feature keeps you warm when temperatures drop.
Sunbeam Fleece Electric Blanket:
Stay cozy and warm when temperatures drop with 10 heat setti... 阅读全帖 |
|
|
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y*****l
发帖数: 5997 | 30 SMARTHEAT INC（睿能集团）
公司行业： 大型设备/机电设备/重工业
公司类型： 外商独资
公司规模： 500-999人
睿能集团（Smartheat Inc.）是一家在美国纳斯达克上市的美国独资公司（股票代码
HEAT），睿能集团(以下简称Smartheat)是一家提供高品质能源设备、技术和能源解决
方案的集团公司，主要业务涉及换热设备在电力、冶金、石油化工、食品、制药、暖通
空调、船舶及造纸等各个工业领域的运用。今天，为了更好地服务于中国地区的客户，
Smartheat投资于中国沈阳太宇机电设备有限公司、桑德克斯板式换热器（上海）有限
公司和睿能（四平）北方能源技术有限公司，主要产品有板式换热器、板式换热机组、
管壳式换热器、螺旋板式换热器、空气冷却器、全自动换热机组、橡胶密封垫片和热能
表及其检测装置等，这三家工厂在 Smartheat统一的质量标准下为客户提供一如既往的
高品质产品和服务，视客户的需求为己任。
Smartheat一直致力于为客户提供卓越的能源服务解决方案。公司设计并制造的
Smartheat系列换热产品能够满足各行业对热... 阅读全帖 |
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m****w
发帖数: 1304 | 31 In fact, you were exactly correct. Heating oil is the same thing as Diesel.
The difference is, when diesel is sold in gas station, road tax is added to
the price. So heating oil is usually cheaper than diesel, although it is
illegal to run your diesel car with heating oil. To enforce that gov't
demands all the heating oil to be dyed (usually red). |
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y********g
发帖数: 3097 | 32 我在IL,虽然冷但是我不需要heated seat,而且有可能relocate 到热的地方。 BMW
Dealer拒绝按照我的要求build车，email我说。
I will not order a car without heated seats.If you don't want the CWP, that'
s fine, but at least heated seats. The way I am pricing this X3 for you, you
aren't even paying for them. A vehicle without heated seats is a strange
configuration, and hurts re-sale value.
我从没有听说过，看来dealer年初是不好negotiate. |
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m**l
发帖数: 15 | 33 MERL is looking for a qualified intern to conduct research in radiative heat
transfer. A solid background in theoretical understanding of heat transfer,
solid state physics, and electromagnetic fields is expected. Research
experiences related to thermal radiation and energy conversion are required.
Expertise in numerical modeling and simulation of electromagnetic fields
and heat transfer, experimental experiences of heat transfer are highly
desirable. The internship duration is 3-6 months with a... 阅读全帖 |
|
a****l
发帖数: 8211 | 34 Please understand conventional heat-pump becomes less and less efficient as
outside temperature goes down (when in heating mode), unless you use things
like geothermal heatpump.
Basically, "it generates least amount of heat when you need heat most". |
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C*******d
发帖数: 15836 | 35 NO!
Heat pump will heat the air inside your house. Because your house's air is
about 65 degrees, when it passes through the heat pump's heat exchanging
element inside your house, its temperature raises about 20 degrees. If your
current house air temperature is 40 degrees, I am sure it won't reach 85
degrees at all after it passes through the element. Exactly how hot your
house can be depends on many factors like outside temperature, house size/
insulation etc. If you don't mind wasting money, yo |
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C*******d
发帖数: 15836 | 36 NO!
Heat pump will heat the air inside your house. Because your house's air is
about 65 degrees, when it passes through the heat pump's heat exchanging
element inside your house, its temperature raises about 20 degrees. If your
current house air temperature is 40 degrees, I am sure it won't reach 85
degrees at all after it passes through the element. Exactly how hot your
house can be depends on many factors like outside temperature, house size/
insulation etc. If you don't mind wasting money, yo |
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j***b
发帖数: 5901 | 37 heat pump一直很耗电。哪怕是开的很低的温度就一直运转。刚才突然发现窗外有水汽
飘过，出去看了一眼，发现heat pump在往外排热气。
heat pump在heating的时候会往外排热气么？不应该吧。大家见过这种情况么？ |
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h*********3
发帖数: 364 | 38 I heard electric heating is more costly than gas heating.
Also, I heard people complaint that baseboard heating is not efficient at
all and can be very costly. You should definitely avoid baseboard heating. |
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h****a
发帖数: 628 | 39 Current interested a house but there oil heating systen are gone. So I need
to re-install a furnace, according to agent. But I want to use a gas heating
.
Do you have any gas heating furnace to recommand which could heating the
while house 4br around 1800 sf.
Any suggestion are appreciated. |
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h****a
发帖数: 628 | 40 1300SF 的房子, 每月暖气的费用会有多大差距?
大家每月如果oil heating or gas heaing or electricity heating, 费用多少呢? |
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m***y
发帖数: 14763 | 41 Nod
Heat pump works by sucking energy from ambient air/soil. The conventional
ones start losing their efficiency when it's below 47°F, and have to fall
back on electric heating, which got low efficiency than gas/oil heating.
Good news is that newer heat pumps can be optimized for low temperature and
keep their full capacity as low as 14 °F. I figure, the moral is, don't
replace it if it ain't broken, because the better are always coming. |
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m********r
发帖数: 350 | 42 刚买的房子，heating用的是heat pump.加热面积不到800尺，室外温度也有30+F。感觉
调高5F，heat pump工作一个小时温度都上不来。是不是坏了？在网上查了一下说heat
pump加热慢，难道慢成这个样子？ |
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n***6
发帖数: 53 | 43 In this area, electric heating is more expensive. Oil heating is a better
option since there is no gas here.
I will check on info on heat pump.
Thanks |
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z****e
发帖数: 555 | 44 how does this mini split work?
The house has no AC. It uses oil for heating the house and hot water.
My agent told me he hasn't seen a buyer walk away from oil heating alone.
But this oil heat will cost about 40,000 in mortgage payment (30 fixed).
I would go with a house newer and has gas heating and 40,000 expensive ... |
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t**d
发帖数: 6474 | 45 heat pump在室外45F以上的时候效率很高，1度电能产生3-5度的热，在30F到40F之间效
率就降下来来，150%-200%左右吧。30F以下基本不能用，要用电阻丝加热。在亚特兰大
，heat pump应该比较有用，因为室外温度40F以上的时间比较多。最好的方案是dual
fuel系统，heat pump 和煤气炉都有，烧煤气的furnace在35F以下使用，heat pump在
35F以上用。运行时具体怎么合算还要看当地电价和气价。 |
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r**********n
发帖数: 146 | 46 好像楼上更像是你说的这种情况，因为楼上的thermostat上有emergency heat option
，如果heat pump工作不正常的话或者室外温度太低，就会启动secondary heat.楼下的
应该是gas furnace，楼下thermostat上没有emergency heat的option。 |
|
t**d
发帖数: 6474 | 47 不一定。如果楼上的有煤气炉，emergency heat就是gas。
楼主的问题，他自己首先要搞清楚室外有几个空调。如果室外只有一个空调机，就是一
个系统，楼上楼下应该是通着的，但是有分区控制，加热和制冷用的是一套系统。如果
外面有两个空调机，楼上楼下是分开的，楼下的是单空调，不是heat pump，暖气用gas
。楼上是heat pump，如果有暖气炉，emergency heat就用gas，否则用电阻丝（这个最
费钱）。 |
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t**d
发帖数: 6474 | 48 heat pump在室外温度40F以上效率很高，低于40F效率很低，基本跟开电炉子差不多，
也就是100-150%的样子。低于30F，就不能用了（外面的那个unit会结成冰疙瘩）。
heat pump最好是dual fuel的，跟煤气炉子一起用，这样Aux heat就烧煤气，费用低。
在北方用heat pump意义不大。在南方室外温度大多时间大于40F的冬天，比较有用。 |
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w*****y
发帖数: 1201 | 49 Auxiliary heat就是辅助加热的，heat pump不工作的时候，就靠Auxiliary heat，
heatpump在温度低于35F，基本上就提供不了多少BTU的了，要靠Auxiliary heat，如果
房子大的话，insluation一般，基本上很难上了65F。
你可以自己买几个space heater，如果有炉子，可以烧炉子了 |
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j******j
发帖数: 54 | 50 87年的房子，用的是 electric base board heating，电费有点贵。
研究了下，gas heating 比较经济，但这里不通 gas。
也听说 heat pump 不错，在 mild winter，比较合算。
各位home owner给说说，heat pump 真的合适吗？什么算 mild winter? 哪个牌子de口
碑较好？ |
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