Home>Discussions>INSULATION & HVAC>Master bedroom is hotter than rest of the house, including the masterbath
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Re: Master bedroom is hotter than rest of the house, including the masterbath

There is not much you can do about having a home in hot, humid Houston, which has the bedroom facing south with the sun beating on its walls all day long. Add to that a vaulted ceiling which limits the amount of insulation possible.

You might consider looking into a separate split A/C system to service that bedroom only. Split systems have become quite popular in the last few years. They allow for handling different areas independantly or as auzilary A/C during especially hot periods. It would allow the bedroom to be comfortable without causing the rest of the house to be like an icebox in an effort to force cool air into the bedroom. Another advantage is that the can be mounted high in the room so that the cool air gently falls. Vents in the floor have a hard time pushing the air upward.

Re: Master bedroom is hotter than rest of the house, including the masterbath

My house is a cape cod layout (2nd floor, 950 sf is part of attic) and 2nd floor is about 4-5 degrees warmer (summer) than 1st (main) floor, and finished basement is another 3-4 degrees cooler than 1st (where my HVAC plant is).
As a 1964 brick, plaster board house and not wanting to throw a lot of money (but a little time), I've assembled some suggestions. I have 1-zone A/C. Specifically, I have a 14x14 BR room that is an issue.

(1) Through-the-wall A/C (or adopt a window A/C to mount thru-the-wall). Hardware cost is low, installation is medium-to-high, and esthetics is low. (For me, brick & no window-mount anything were deal killer). Also, doesn't help in winter unless A/C is cool/heat.
(2) Mini-split system suggested by ordjen - - hardware is about $1,000, installation is typically not DIY; professionally installed w/ hardware is $2,500-$3,000.
(3) Increase air fow to 2nd floor by turning down (or off) louvres in all registers not on the 2nd floor -- posters have both said OK, or not OK (makes compressor work harder and wear out your system sooner) to do this -- I don't know, but the compressor explanation doesn't convince me (although if they're right, I'm in for a big bill sooner than normal). My experience -- I did this and can't tell what's happeninig -- my sense is that my hotter 2nd floor marginally gets more cooled air.
(4) In my 14x14 problem room, only 1 register on an exterior wall. I could probably increase the register size, but can't imagine a 2nd register. (Didn't try this.)
As the register faces the door, I close the door and it makes a difference in comfort -- more cooled air is trapped, but warm air isn't pulled by the return in the Hall.
(5) Overhead fan to circulate air -- moving air has a marginal increase in comfort.
(6) Use a filter with lower MERV rating during the hottest months -- I use a less expensive #4 instead of #12-13 pollen/dust mites super duper filter.
With steps 4, 5 & 6, the room is bearable in the summer with blinds down without over-cooling the main 1st floor.
In NoVa. (1.5 miles from CIA Langley), July & August are indoor months for me. A/C runs 12-18 hours during the hotter/hottest days so the plant seems sized correctly (not under and not over).

Re: Master bedroom is hotter than rest of the house, including the masterbath


My last home was a split level. In summer, I used to let the furnace fan run around the clock. This helped distribute the colder air which wants to gravitate to the lower level.

If the upstairs room has a direct air return in the room, close the door to the bedroom. Again, the cold air wants to run downstairs. If there is no air return in the room, add one if possible!

In rooms with high ceilings, don't use the ceiling fan when air-conditioning. A ceiling fan is going to push the hot air down from the ceiling. Let it stay up there! I have this problem in my present home that has 15 foot ceilings in the family room. In hot weather, the ceiling fan fights the air-conditioning. Ceiling fans are fine before the AC is neccessary, but once the AC is on, leave that ceiling fan off.

That same family room/kitchen had over 500 square feet served by only two vents. It was hot in summer and cool in winter. I had the HVAC people come in and run another line with a larger diameter to the middle of the long wall. I had also added a second patio door in the middle of that long wall. All the more reason for more conditioned air for that space. The room is now much more comfortable year round!


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