One room extension is cold


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Old 02-04-21, 09:42 AM
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One room extension is cold

I have a hydro air zone for the top floor of my house with a large central return duct in the hall. Before i owned the house, an extension was added that included a masterbathroom on the second floor.

The bathroom is 10x10ft with a arched ceiling that probably hits 12ft. It is exposed on 3 sides and the roof. It shares one wall with the original structure of the house.

For heat, they tied in one 12x6 register to feed the room from the upstairs HVAC system. This certainly can heat the bathroom up fine. The problem is, the heat loss is higher in this room than the rest of the upstairs. The thermostat is in the hall upstairs. The upstairs can hold 70F all day after heating up in the morning. The bathroom will hit 70F in the morning but steadily fall to 55F before the main house upstairs even needs heat.

Any ideas on how to remedy this? I was wondering if maybe some new arrangement might work with the ducting. I imagine you can't zone just one room since it wont support enough air flow for the blower.

 
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Old 02-04-21, 10:27 AM
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I don't think ducting will fix it since the problem occurs when the system is off and that room happens to cool faster. Air circulation would be my first guess. Possibly leave the air handler fan on continuously during winter so all areas of the upstairs zone stay closer to the same temperature.
 
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Old 02-04-21, 08:47 PM
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Thanks, PD. That is probably the only option here short of opening everything up and reinsulating. I wonder if it will cause the downstair zones to run a lot since the upstairs return duct is at the top of the staircase.
 
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Old 02-05-21, 05:04 AM
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Heat rises and cold sinks. Any open passage between two floors will cause HVAC difficulties so your downstairs heat is flowing upstairs whether or not the upper unit is running. If you ever rode a department store escalator and saw clear plexi panels hanging from the ceiling around the escalator hole it was to help control the airflow a bit.
 
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Old 02-05-21, 06:40 AM
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Yeah so knowing that, then does it not make sense to turn the upstairs colder than the downstairs during the day? will doing that just make hte zone at the bottom of the stairs run all day because most of its heat is just escaping to the second floor? You can feel the cold air dropping down the stairs during the day. The upstairs is usually 67 and ecobee will sometimes throttle it back to 65 if noone goes upstairs. The wife has me keep the downstairs at 70F during the day.

Thanks
 
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Old 02-06-21, 06:49 AM
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Running the furnace fan continuously is a good idea.

In our cold climate it is common practice in new construction or with a remodel to install electric in-floor heat to even out the temperature of a centrally heated home.
Another option and more simple to install would be an electric baseboard heater or a wall insert heater as a supplement.

Unfortunately other than running the furnace fan there really is no way to easily modify what you have.
 
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Old 02-06-21, 07:59 AM
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Thanks, Guys. The previous owner did put an electric kickspace heater in (not the wisest move in a bathroom but oh well). I am wiring it up to a GFCI and connecting a thermostat later today. It will have to do until we gut reno the bathroom next year. I'll also give running the fan constantly a try and see how tolerable that is around the house (not sure if we will get blasted with cold air).
 
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Old 02-06-21, 08:18 AM
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Originally Posted by pbct2019
The bathroom will hit 70F in the morning but steadily fall to 55F before the main house upstairs even needs heat.
First, I'd check how the venting for the bathroom was run. Does is go through the roof, or through a wall? If it's vented through the roof, you may be having a combination of warm air leaking out, and cold air leaking in. You might be able to find a 'draft stopper' or louvered design that is more draft resistant.


Second, check the light switch and other fixtures - do you feel any cold air leaking in around the switches, outlets or light fixtures? Since you're exposed on 3 walls and ceiling, any air gap will likely let cold air in, even if the walls are well insulated.
 
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Old 02-09-21, 07:15 AM
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Thanks, guys. the exhaust goes through a side wall right to the outside. I would suspect it leaks (I sometimes hear its damper blow open and closed on a really really windy day but usually it stays closed).

Walls are cold to touch but no clear leakage from outlets or lights. Ive covered the room with a FLIR gun and saw no obvious cold spots. My guess is they just didnt insulated well enough for the amount of exposure and potential heatloss the space could have.

Running the blower fan all day helps a lot; not just in the bathroom but actually evening out temperatures throughout the house since the upstairs hydroair feeds supplemental heat and primary AC to several downstairs rooms.

Thanks again for the help.
 
 

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