Greater Lansing
Furnace combustion testing
A furnace with a cracked heat exchanger heats the house perfectly well and gives no sign in the vents. It is found by measurement or it is not found.
What is actually wrong
A furnace burns fuel on one side of a steel heat exchanger and blows house air across the other side. The two are never supposed to meet. The exhaust goes up the flue; the warm air goes to the rooms. Everything about combustion safety comes down to whether that separation is intact and whether the exhaust is actually leaving.
What a test measures is carbon monoxide in the flue gases, whether draft establishes properly, and whether the readings change when the blower starts. That last one matters: a crack in a heat exchanger often shows up as a reading that shifts the moment the fan comes on, because the blower pressure is pushing house air into the combustion side or pulling exhaust out of it.
None of this is visible. A furnace with a cracked exchanger heats the house perfectly well and gives no sign in the vents. It is found by measurement or it is not found.
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 and call 911 or your gas utility from outside. Consumers Energy runs a 24-hour emergency line and will come out free. A scheduled test is not what you need in an emergency.
- WE DO NOT SERVICE, REPAIR OR REPLACE FURNACES, AND THAT IS A LICENSING LINE RATHER THAN A PREFERENCE. Michigan mechanical contractor licensing covers heating work and Haslett Handyman does not hold it. What is offered here is measurement and a written report.
- A FAILED TEST GOES TO A MECHANICAL CONTRACTOR, NOT BACK TO US. You are told plainly what the readings were, what they mean and what to ask for. We do not then quote the repair, which also means we have nothing to gain from the result.
- Testing is not a substitute for annual servicing by a heating contractor, and it is not a heat exchanger inspection by camera.
The work itself
What actually gets done
Measure carbon monoxide in the undiluted flue gases once the appliance has run long enough for the reading to settle.
Watch what the readings do when the circulating blower starts, which is where heat exchanger problems announce themselves.
Check that draft establishes from a cold start and holds.
Test under worst-case depressurization, with exhaust fans and dryer running, because that is when a marginal flue fails.
Inspect the vent connector and flue for corrosion, slope, disconnection and blockage, and check that combustion air is actually available to the appliance.
Give you the readings in writing, so a mechanical contractor is handed evidence rather than an opinion.
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 every gas appliance is tested together, which is the only version that answers the question properly — appliances on a shared flue affect each other.
Whether it runs alongside a blower door, where the worst-case condition is already being created and the extra cost is small.
Access to the flue and vent connector, and whether the appliance is in a tight closet or a crawl space.
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 that every level of the house has a working carbon monoxide alarm. Nothing here matters more than that.
- Look at the flue pipe where it leaves the furnace for rust, soot staining or a joint that has separated.
- Notice whether anyone in the house gets headaches that clear up when they leave it, and whether that started when the heating season did.
- Look at the burner flame if it is visible. Steady and blue is right; yellow, lazy or lifting is worth mentioning when you book.
- Note the age of the furnace and whether it shares a chimney with a water heater, and have the last service record to hand if there is one.
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
Can a test find a cracked heat exchanger?
It can find strong evidence of one — particularly readings that shift when the circulating blower starts, which is the classic signature. It is not a camera inspection of the exchanger itself, and anything suspicious goes to a heating contractor who can open it up. What the test gives you is a reason to call one, with numbers attached.
Why do you not fix what you find?
Because heating work in Michigan requires a mechanical contractor license and we do not hold one. It has a useful side effect: we have nothing to sell on the back of a bad reading, so the reading is just the reading.
My furnace was serviced last year. Do I still need this?
They answer different questions. A service is about whether the appliance runs well. A combustion safety test is about whether the exhaust is leaving the building under the conditions your house actually creates — every fan running, doors shut, on the coldest day. A furnace can be freshly serviced and still backdraft in a house that has been tightened up.
Should this be done with the water heater test?
Yes, where both are gas. Appliances sharing a flue influence each other, and testing one alone can pass something that fails as a pair. Doing them together is barely more than doing either on its own.
Book a combustion safety test
We measure and we report — we do not service, repair or replace furnaces, because heating work in Michigan needs a mechanical contractor license and we do not hold one. The useful side of that: we have nothing to sell you on the back of a bad reading. If you suspect carbon monoxide right now, do not book anything — leave the building and call 911 or Consumers Energy from outside.