Thread: Is HVAC supply required in bathrooms?

I inspected a 7 year old house today, and I check the registers in each room to make sure they are functional. 2 of the bathrooms had HVAC registers, but the 3rd did not. I called this out as a deficency, but I was wondering if there was any code requirements that back up my findings? I have been looking in my books and cannot find anything, but I thought there was something about size of the room, etc?

Can anyone give me a little assistance on this, because I know the Sellers are not going to correct this condition without something to reinforce my recommendation.

Thanks much and be safe - jdj

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Same question in archives:
Heated Bathrooms - Home Inspection & Home Inspector Services For Inspections and Inspectors

Originally Posted by JD Johnson

and cannot find anything,

That's because it's not in there.

In my area in NC you are required to have a duct in a bathroom and a separate duct in a toilet room. I have found numerous problem with this as the bath and toilet rooms overcool and overheat. The fix has been to put dampers in the duct runs.

Personal opinion.

You need air flow in ever room in the home and even in larger closets. Return air in any room with a door.

In my area in NC you are required to have a duct in a bathroom and a separate duct in a toilet room. I have found numerous problem with this as the bath and toilet rooms overcool and overheat. The fix has been to put dampers in the duct runs.

James, what part of this does not apply in NC?

From the 2003 IRC…
“R303.8 Required heating. When the winter design temperature in Table R301.2(1) is below 60°F (16°C), every dwelling unit shall be provided with heating facilities capable of maintaining a minimum room temperature of 68°F (20°C) at a point 3 feet (914 mm) above the floor and 2 feet (610 mm) from exterior walls in all habitable rooms at the design temperature. The installation of one or more portable space heaters shall not be used to achieve compliance with this section.”
And from the definitions in chapter 2... “HABITABLE SPACE. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces.”

If bathroom aren't habitable spaces, why are they so hard to get into most of the time?

rick

Vern,

As I read that it is a performance, not a design, spec - it does not require a register (or any other particular ventilation method), only an acceptable level of performance without specifying how it is to be achieved.

For example at new condos in Chicago (even high-end units) you will sometimes see a permanently operating common bathroom exhaust system and undercut bathroom doors to supply the makeup air.

I always note the drawbacks of arrangement, but it's acceptable to Chicago's municipal inspectors.

Originally Posted by Rick Hurst

If bathroom aren't habitable spaces, why are they so hard to get into most of the time?

rick

That's why you don't want to make them too comfortable with heating and cooling! It's bad enough as it is!

It is pretty common in this area to not put an HVAC register in a bathroom if it has 4 inside walls. Usually powder rooms (no shower or bath) with no outside walls.
Lee

Thanks for the info, I had tried to search the archive posts, but must not have been using the right keywords - (I was more concerned about cooling than heat). This bathroom was a 3/4 bath, with two outside walls. I'll keep it in my report as a recommendation, but tell the Buyers not to expect the Seller to "upgrade" the installation.

Have a great one! - jdj

Rick nailed it; bathrooms and toilet spaces are not considered habitable space, hence conditioned air is not required, but ventilation is.

Michael, I think you are mixing apples and oranges?

Ventilation in a bathroom is not heating and cooling. I think there is a code section preventing tying two or more vents together but would have to research to be sure.
Out of curiousity looked up code. Old book 1991 but I think still applies.
308.2.3 code does allow combining similal vents (bathroom), just can't combine any kitchen vents.

Originally Posted by Ted Menelly

Personal opinion.

You need air flow in ever room in the home and even in larger closets. Return air in any room with a door.

Just because I can. I will repeat myself.

Personal opinion.

You need air flow (conditioned air) in ever room in the home and even in larger closets. Return air in any room with a door (accept closets and bathrooms). You also do not want to close supply vents for unused rooms. Heat and moisture build up in summer and cool and damp in winter. You want the entire living area of the home to have well circulated air, warm in the winter and cool in the summer.

For what ungodly reason would you not want heat and AC in a bath. Just don't understand. Don't care what any book might say. I have always seen to many concerns with unconditioned air in any room, including bathrooms. Bathroom especially. You certainly do not want a cold bath in the winter or hot humid air and damp everything in the summer. You have to move the air and I am not talking ventilation. No one keeps a ceiling bath vent on after they leave the bathroom. To me this is an issue that states to hell with any book that does not make sense. The only homes I have ever seen no conditioned air in a bath were older homes and they always had moisture issues even with ceiling vents that are practically never turned on.

Just my opinion

Just my opinion.

Did I say, Just my opinion.

Originally Posted by Vern Heiler

James, what part of this does not apply in NC?

From the 2003 IRC…
“R303.8 Required heating. When the winter design temperature in Table R301.2(1) is below 60°F (16°C), every dwelling unit shall be provided with heating facilities capable of maintaining a minimum room temperature of 68°F (20°C) at a point 3 feet (914 mm) above the floor and 2 feet (610 mm) from exterior walls in all habitable rooms at the design temperature. The installation of one or more portable space heaters shall not be used to achieve compliance with this section.”
And from the definitions in chapter 2... “HABITABLE SPACE. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces.”

The latest is a new $850,000 house done last month in Cary, NC. The HVAC contactor was still there working and we talked about how silly it was to put a register in a toilet room. He said that the AHJ requires it so he does it.

IRC – 2006 - M1506.2 Recirculation of Air: Exhaust air from bathrooms and toilet rooms shall not be recirculated within a residence or to another dwelling unit and shall be exhausted directly to the outdoors. Exhaust air from bathrooms and toilet rooms shall not discharge into the attic, crawl space or other areas inside the building.
The under-lined words is a code change from the 2003 IRC.

Point of interest; IRC 2006: Natural light and ventilation (openable windows) for habitable rooms is no longer a code requirement per Section 303.1 except for 310 - Exceptions 1 (EE & R) and 2.

Originally Posted by Jerry McCarthy

Point of interest; IRC 2006: Natural light and ventilation (openable windows) for habitable rooms is no longer a code requirement per Section 303.1 except for 310 - Exceptions 1 (EE & R) and 2.

On that WC Jerry and I agree and disagree.

Where I disagree - I say it is still a requirement as no one is going to build to fully meet the exception - thus leaving the requirement in place.

Where I agree - 'Could' someone build to meet the exception to the requirement and not have to provide natural ventilation and daylight? Yes.

'Is it likely' that will happen? I doubt it.

Short of something like a bomb shelter, that is. (Which is possibly why it is allowed, without an exception like that in there, it would not be feasible to build a closed bomb shelter.)

Instead of bombs, think 'high winds' - like a tornado 'safe room', or a hurricane 'safe room', or even a NY 'safe room'. (What was the name of that movie? )

That exception could also be applied to "Entertainment Rooms" with the right systems in place. Allowing them to not have windows.

I can only speak on how we do things in regards to this scenario.

If the heat loss/gain for the home comes out that I need something like 4-10 CFM in an interior bath you can bet I'm not going to waste the material to install a supply outlet that I will be completely closing/dampering off.
Most bathrooms are very overconditioned as in way too much airflow.

If the bathroom has any exposed exterior walls yes it needs to be conditioned to some degree.
If there are moisture issues in a bathroom don't immediately assume the culprit is no supply outlet in the bathroom.

I see the massive holes under tub enclosures as more of an issue in an interior bath than this.

For the life of me I cannot comprehend the thought behind not wanting a cool dry bathroom in the summer and a warm dry bath in the winter. It does not have to be a 16 inch square supply vent.

I don't know, call me foolish or thick. I just don't get the argument other than strictly arguing for codes sake.

Originally Posted by Ted Menelly

For the life of me I cannot comprehend the thought behind not wanting a ... dry bathroom in the summer and a ... dry bath in the winter. It does not have to be a 16 inch square supply vent.

Ted,

The a/c and heat supply to the bathroom *is not* there to "dry" it out.

That's what bathroom exhaust fans are there for ... to exhaust that moisture laden air.

Sure, not many people operate their bath fans, but - if you want a "dry bathroom" ... that *is* what the exhaust fan is for. Use it or not - your choice.

If you want the bathroom dry use dedicated dehumidification.

Most typical residential exhaust fans don't move anywhere near enough air to provide the proper air changes a bathroom needs.

If the bath is exposed to an exterior wall then it needs to have air supplied to it from the HVAC system if it's surrounded by conditioned space as is the case with an interior bath there should be technically very little sensible load on that room besides body and light fixture heat.

Why thank you Mister Jerry

Yes I know why the bath vent is there. My point was, a nice cool dry bath in the summer and a warm dry bath in the winter, considering most baths, not all but most do have a window and or outside wall.

Oh, about the bath vent in the ceiling. No one runs them long enough to get rid of the moisture. Some folks do not even turn them on.

Yes I know that the heat and AC are not to dry the bathroom, but it does and works quite nicely.

I wonder why people put radiant floor heat in to have a nice warm bathroom in the winter?

That is my point and it does help it keep the bath dry.

That's all, no offence to any of the nice folks. Like I said way up there somewhere on this thread.

Just my opinion.

Although, some people might like nice hot stuffy (or cold) damp bathrooms. Who new!

Oh yeah, did I mention my opinion on larger closets. Shoes, clothes, no air flow, stuffy, (or cold or warm if against an outside wall) Just my opinion.

Actually I disagree with EC Jerry in that we really don’t disagree at all because the code writers, with more than a little influence from our friends at NAHB, got those exceptions through which does not mean that I/we should applaud them. First of all, I’m a fresh air nut, and would not be long in a room with no natural light or natural ventilation. Talk about an energy waste with all those friggin fans working overtime to get rid of my cigar smoke!

Seriously, I’ve never inspected a home without heat registers in the bathrooms and installing an additional exhaust fan is just pain old common sense when you consider the issues with accumulated moisture and the dreaded M word so that’s a good code, right?.

What I suspect is through some back-room arm twisting from the NAHB this code change result in making all those basement mother-in-law units, au pair quarters and media rooms “habitable space” which also makes them “saleable” square footage rather then just extra storage space. However, I could be wrong?

Originally Posted by JD Johnson

I inspected a 7 year old house today, and I check the registers in each room to make sure they are functional. 2 of the bathrooms had HVAC registers, but the 3rd did not. I called this out as a deficency, but I was wondering if there was any code requirements that back up my findings? I have been looking in my books and cannot find anything, but I thought there was something about size of the room, etc?

Can anyone give me a little assistance on this, because I know the Sellers are not going to correct this condition without something to reinforce my recommendation.

Thanks much and be safe - jdj

"The 3rd room maybe having transfer grills or door louvers where supply air from the adjacent room or the hallway is transferred to the toilet and exhausted by the toilet exhaust which is acceptable as per International Mechanical code, section 403.2.2"

Originally Posted by Chan peace

"The 3rd room maybe having transfer grills or door louvers where supply air from the adjacent room or the hallway is transferred to the toilet and exhausted by the toilet exhaust which is acceptable as per International Mechanical code, section 403.2.2"

In our cold area of the world, heat is required in all bathrooms that are on an exterior wall to prevent freezing. Baths that have all interior walls and the areas adjacent to these walls have heat do not REQUIRE heat supply, but it is prefered for comfort.

Originally Posted by Ken Amelin

In our cold area of the world, heat is required in all bathrooms that are on an exterior wall to prevent freezing. Baths that have all interior walls and the areas adjacent to these walls have heat do not REQUIRE heat supply, but it is prefered for comfort.

Ken,

What is the code wording which requires That?

Curious because typical code wording REQUIRES protection of pipes from freezing (supply .... AND ...DWV), but does not require what you describe (if the piping is protected from freezing as required by typical code wording, heating a bathroom to keep the pipes from freezing would not be needed).

Originally Posted by Jerry Peck

Ken,

What is the code wording which requires That?

Curious because typical code wording REQUIRES protection of pipes from freezing (supply .... AND ...DWV), but does not require what you describe (if the piping is protected from freezing as required by typical code wording, heating a bathroom to keep the pipes from freezing would not be needed).

Here's what I found.

MA Code 248CMR 10.05 (8)(c) - Freezing Prevention
1. No water supply or drainage piping shall be installed outside of or under a building in an exposed, open or unheated area.
2. For water supply or drainage piping that is installed in an exterior wall, unconditioned space, or similar areas that may be directly influenced by freezing temperatures, adequate provisions shall be made to protect pipes from freezing.

Originally Posted by Ken Amelin

Here's what I found.

MA Code 248CMR 10.05 (8)(c) - Freezing Prevention

2. For water supply or drainage piping that is installed in an exterior wall, unconditioned space, or similar areas that may be directly influenced by freezing temperatures, adequate provisions shall be made to protect pipes from freezing.

Number 2 allows many methods of protection for piping in exterior walls - and 'heating the bathroom' cannot be counted on for that ... maybe if the pipes are on the inside of the wall insulation, but that would put the pipes at risk of nails and screws through the drywall.

Number 1 is not applicable because the piping in the exterior wall is not "outside of or under a building"

Added with edit for clarification:

"maybe if the pipes are on the inside of the wall insulation" - as in 'between the insulation and the drywall', not as in 'at some point within the insulation itself'