Fresh air intake requirements for a gas water heater?

What would be the fresh air intake requirements for a 36,000 BTU natural gas water heater?
I used to have a 72,000 BTU 80% natural gas furnace, and a 36,000 BTU natural gas water heater. The fresh air intake for both was provided by a vent (i.e. hole) in my basement wall in the furnace room to the outside.
I've since upgraded my furnace to a 93% efficiency model, so its fresh air intake is supplied by a PVC pipe that runs outside through the concrete foundation (through a new hole).
So I'm wondering (hoping) whether I can make the original vent smaller, as it now only serves the water heater, and all the cold air coming in from the outside is wasting energy needlessly.
The furnace installer (who was pretty junior as he was young and screwed a couple of things up and I had to call the company back to fix the problems with an older repair man) had said to leave the original vent alone. But I would think that the water heater (36,000 BTU) could suffice with a smaller fresh air intake vent than what was originally done to serve both the water heater and the furnace? Assuming the vent size is related to the BTU capacity, the gas water heater represents 1/3 of the original setup (36,000+72,000).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I lived in three houses with gas water heaters. They had no vents at all. I see no reason it could not be reduced a bit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Not knowing the exact situation, you need 1 sq inch per 10k btu of fresh air, one air inlet high and one low. Respond directly to me and I can send you the ~4 meg pdf file. That I have or you can use google like I did
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The installation manual for the heater should have pretty clear specs on air intake. These things are calculated by the manufacturer, just so the installer or homeowner doesn't have to "guess". Not that it stops them from guessing anyway :-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I dought you need an intake, it just cools the house, close it and check for no flue draw, houses leak alot of air. Get a blower door test to confirm it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If the water heater is in the durnace room and the furnace room is closed off from the rest of the basement ; the fresh air inlet may still be required, depending on the size of the furnace room. You can probably reduce it in size. I don't have my code books with me, but SQLit may have all you need. Have him email it to you.
Stretch
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jonny snipped-for-privacy@hotmail.com wrote:

Check with your city or call your local energy company. In my city fresh air intakes are only required for gas furnaces. Frankly, it's not a bad idea at all to have one for the other gas appliances anyway, to reduce the risk of backdrafts, but you're best off finding out what is code in your area.
HellT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hell Toupee wrote:

Thank you all for the replies. I'll call the energy company to confirm whether it is needed or not (my hot water tank is a rental). Last night I spoke to a few friends and family members living in relatively new houses, and none of them had a vent specifically for their hot water tanks, so it may not be needed at all.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 19 Jan 2006 06:16:20 -0800, jonny snipped-for-privacy@hotmail.com wrote:

Of all the houses we have owned or rented in six states we have never had a separate air intake for our gas water heaters. Typically, the heater is in the garage. Sometimes it is inside the house, like where we live now. The heater just draws its air from the house or garage. I suppose if it was in a closet with a sealed door, you might need a vent.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You're sure not current on code.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net
"Dick" <LeadWinger> wrote in message wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
What code would that be?
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Uniform plumbing code. Table 5-1
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I don't need to be current on code. The people who built our houses are the ones who had to be current on code. All of our houses were built by major contractors, so I can only assume they and the building inspectors knew what they were doing.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.