Can I cover the hall utility door vent?

Get a thorough home inspection on this space. Headaches, sneezing and bloody noses can be due to off gassing from this unit. Call out the gas company too, they will inspect for free. Get her into the pediatrician asap and show him or her these photos.

And find out how much it would be to have this relocated to the garage or outside.

Most buildings have the door vented for safety reasons. If the heater is gas then be sure to find out the correct solution before closing off the vent. Try adding a humidifier to your home to resolve the dryness issue. If you cannot afford one attached to the furnace then buy a portable one for your daughter's room.

I don't know an awful lot about this, but I believe removing the vent would be a dangerous thing to do, especially since you have both your hot water heater and your furnace in there.

I see that you have vents *under* the door, too (clicked through and found the other photos). I wonder if those might be good enough? I'm not positive how they're set up. I assume your plumbers told you to remove that vent because of the smell in your daughter's room? Do they think exhaust fumes are getting in there?

I wish I could offer more help, but I think perhaps a contractor who specializes in installing furnaces might be the one to answer your question.

DO NOT, I REPEAT, DO NOT COVER THE VENT! The furnace and hot water heater need combustion air to burn properly and be able to vent the flue gases out the chimney. Call an HVAC tech to assess your dry air and odor problem. It can be as simple as installing a humidifier or can be as severe as improper flue gas venting. Natural gas and the risk of Carbon Monoxide are not something to play with.

You can have a whole house humidifier installed that is regulated with a thermostat like device. It was a game changer for our family. Less dust in the air and my nose bleeds almost completely went away.

The vent in the door is for combustion air. Flame needs air to burn. Closing the vent the equipment will suck air from underneath and around the door starving for air. The flue gases go up the chimney and outside. I don't see why changing the ducts will do anything. If they have been working and properly sized they should pose no problem. Close the vent and the carbon monoxide will be going off. Glad you DO have them. Room humidifier will help but a whole house humidifier mounted on the furnace, properly sized, would work much better. May I suggest in getting a HVAC contractor referral from Home Depot. They have contractors that install for their purchases.

If the vent is closed, the furnace and water heater won't have combustion air, as William said. The only other solution is to provide combustion air from elsewhere, perhaps by means of a duct from outdoors, but that would be a job for an HVAC expert.

Thank you everyone. Unfortunately, out of all the HVAC people that came out only one gave me an estimate today. Turns out because of the low roof and lack of access to the ducts many contractors do not want to do the work. Our utility closet in the hall is not vented correctly. We will have it vented correctly, the ducts cleaned and insulated. I'm praying this will help.

You guys are amazing thank you again!

Veronica, I work in HVAC. DO NOT COVER THIS!!

This vent is for make up air. What happens, if you cover it, is that the appliances will be starved for air. They will not burn efficiently and can cause a backdraft situation which is DEADLY!

Many HVAC professionals and plumbers do not understand the ventilation aspect of heating, ventilation and air conditioning. Rather than a PLUMBER, have your gas company identity the source of your make up air. If a new make up air has been installed inside the closet, then there will be an open pipe directly to the outside. A lot of people don't like this because it dumps cold air in the house and they stuff a rag in it.