Greater Lansing
Water heater combustion testing
Nothing forces the exhaust up a conventional water heater's flue except the fact that hot air rises. Switch on enough fans and the house wins that argument.
What is actually wrong
A conventional gas water heater burns fuel in an open space under the tank and relies on hot air rising to carry the exhaust up a flue. There is no fan making that happen. It works because warm gas is buoyant, and it stops working when something in the house beats that buoyancy.
That something is usually the house itself. Run a bathroom fan, a kitchen hood and a clothes dryer at once and you pull air out faster than it can get back in, and the easiest replacement path is down the water heater flue. When that happens the exhaust comes out of the draft hood into the room instead of going up. It is called spillage, and the gas in it includes carbon monoxide.
The test is to run the appliance, measure what is in the flue and whether the draft establishes, and then do it again with the house pulled into the worst state it realistically reaches. A water heater that drafts beautifully in a still house and backdrafts when the dryer is on has not passed anything.
Where this stops
When it is not a handyman job
This is at the top of the page rather than the bottom because getting it wrong costs you a wasted visit. Insured, and no contractor license is claimed or implied — the Michigan residential builder license is not held.
- THIS IS A NEW SERVICE AND THE RECORDS CARRY NO COMBUSTION TESTS YET. BPI Building Analyst certification is in progress through the Consumers Energy program at Jackson College and completes in November 2026. It is not claimed as held.
- IF YOU SUSPECT CARBON MONOXIDE RIGHT NOW, DO NOT BOOK A TEST. Leave the building, then call 911 or your gas utility from outside. Consumers Energy runs a 24-hour emergency line and will come out free. This service is for finding a problem you do not yet have symptoms of, and it is not what you need in an emergency.
- TESTING, NOT GAS WORK. Replacing a water heater, altering gas piping or re-lining a chimney is licensed trade work and is referred. Where a test fails, you get the readings and the evidence to hand to whoever does the repair.
- A combustion test is a measurement taken on one day in one set of conditions. It is not a warranty that the appliance is safe forever, and nothing replaces working CO alarms on every level of the house.
The work itself
What actually gets done
Measure carbon monoxide in the undiluted flue gases, with the appliance running long enough for the reading to settle.
Check that draft establishes at the hood within a reasonable time from a cold start, which is when a marginal flue shows itself.
Repeat the test under worst-case depressurization — exhaust fans and dryer running, interior doors positioned to make it hardest — because that is the condition the house actually reaches.
Inspect the vent connector and flue for corrosion, disconnected joints, back-pitch and blockage.
Check for an orphaned water heater, which is a tank left on a chimney sized for a furnace that has since been replaced by a sealed unit.
Report in writing, with the readings, because a combustion result is only useful next to the numbers it was taken from.
This work sits inside Home Energy Assessment, which carries the invoiced price bands for the trade with the sample size printed beside every figure.
What it costs
There is no price list for this, and here is what actually decides the number.
The same three words describe a twenty-minute job and a two-day one. Rather than publish a figure that is wrong for one of them, here is what moves it — so you can work out roughly which end of it you are at before anybody comes out.
Whether it is one appliance or every gas appliance in the house tested together, which is the version that actually answers the question.
Whether it is standalone or part of a full assessment, where the blower door is already set up and the worst-case test costs very little extra.
How accessible the flue and vent connector are along their length.
How to get a real number
Somebody comes out, looks at it properly, and you get a fixed price in writing with the work set out line by line and the exclusions written down as plainly as the inclusions. Coming out to do that is not charged for, and neither is working out what is wrong. If something is found once a wall or a floor is open, it is priced as a written change order and you decide before the work carries on rather than after it is billed. Materials are supplied at cost with the receipt attached, first-time customers get 10% off labor, and labor carries a one-year craftsmanship warranty.
If this is happening right now
What to do in the next five minutes, and what happens when you ring.
Before anybody arrives
- Check you have a working carbon monoxide alarm on every level, and that none of them is older than its replacement date. This matters more than any test we could sell you.
- Look at the vent pipe above the water heater for rust streaks, soot, or a joint that has come apart. Rust at the draft hood is exhaust condensing where it should not be.
- Notice whether the pilot or burner ever goes out when the dryer or a bathroom fan is running.
- If the water heater sits in a closet with a louvered door, do not block those louvers with storage. That is its combustion air.
- Count the gas appliances sharing a chimney and note whether the furnace is a sealed unit with a plastic pipe to the wall. If it is, the water heater may be orphaned.
Call the business line
(517) 505-7135Answered Monday to Friday, 08:00 to 18:00. There is no out-of-hours line and this page is not going to invent one — outside those hours, leave a message with the address and what is happening, and it is picked up in the morning.
On the call you get asked what is happening, what else in the building is affected, and whether it is still getting worse. That is how it gets decided whether this is our job at all — and if it is not, you get told that on the phone rather than after somebody has driven out.
- No trip charge
- No call-out fee or minimum
- No diagnostic fee
- No charge for a return visit
True across all 84 written quotes this company has issued. Most contractors in this market charge to turn up.
Or send the detailsWhen the right answer is not this company
- You can smell gas
- Leave the building and call the utility from outside. Not us, and not later.
- Water you cannot stop
- Your main shut-off first, then a licensed plumber. Every minute of this one costs money.
- Sewage backing up, or several fixtures at once
- A licensed plumber with a camera. That is the shared line, not a fixture, and a cable down one sink will not touch it.
- Sparking, scorching or a burning smell at an outlet or a panel
- Breaker off, and a licensed electrician. Electrical work here is repair and like-for-like replacement, and this is neither.
- No heat, or heating and cooling equipment that has failed
- A licensed mechanical contractor. That trade is not offered here at all, and knowing that in one phone call is worth more than a visit.
Questions people actually ask
What is backdrafting?
Exhaust gas coming out of the appliance into the room instead of going up the flue. In a conventional water heater nothing forces the exhaust upward except its own buoyancy, so anything that pulls air out of the house harder than it can leak back in — bath fans, a kitchen hood, a dryer — can reverse it. That is why the test is run with those things on.
I have a CO alarm. Is that not enough?
An alarm is essential and you should have one on every level. It is also a last line, set to sound at concentrations well above the point where a problem exists: it tells you the air in the room has become dangerous, not that your appliance is spilling. The test measures the flue gas itself and under conditions the house only occasionally reaches.
What is an orphaned water heater?
When a furnace is replaced with a modern sealed unit that vents through a plastic pipe in the wall, the water heater is often left alone on a masonry chimney that was sized for both appliances. One small appliance cannot warm that much flue, so the exhaust cools, drafts poorly and condenses inside the chimney. It is a very common consequence of a good furnace upgrade and it is specifically looked for.
Do you fix what the test finds?
Some of it. A disconnected or back-pitched vent connector is ordinary work. Replacing the water heater, altering gas piping or lining a chimney is licensed trade and is referred, with the readings handed over so the next person is not starting from nothing.
Book a combustion safety test
Tell us how many gas appliances are in the house and whether they share a chimney — testing them together is the only version that answers the question, because appliances on one flue affect each other. If you are smelling exhaust or anyone has headaches that clear when they leave the house, do not book: leave the building and call 911 or Consumers Energy from outside. They come out free, at any hour.