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Good anemometer for HVAC

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  • Feb 21st, 2021 7:30 pm
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[OP]
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Nov 28, 2016
18866 posts
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Out west

Good anemometer for HVAC

Choices are endless, and prices ranges are to.

Whats a good anemometer to measure CFM from supply vents in a home. Im adjusting dampers, and want to see the difference in farther vents as I adjust, instead of just "it seems better" feeling with your hand
11 replies
Deal Addict
Jun 16, 2009
2492 posts
917 upvotes
Woodbridge
Testo makes the best tools However it’s difficult to justify the cost as being home owner

https://www.testo.com/en-US/testo-410-2/p/0560-4102

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quote=WikkiWikki post_id=34093495 time=1613834258 user_id=1374037]
Choices are endless, and prices ranges are to.

Whats a good anemometer to measure CFM from supply vents in a home. Im adjusting dampers, and want to see the difference in farther vents as I adjust, instead of just "it seems better" feeling with your hand
[/quote]
HVAC Professional. Committed to customer, not brand.
Humidifier 2020 Group Buy
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May 23, 2009
2795 posts
1260 upvotes
Mississauga
I bought this one for about $20 around 5 years ago to balance my vents.

I adjusted my vent to push more airflow to the 2nd floor. It worked well enough but could not really fix my main airflow issue which was more noticeable in the heating season. My vents furthest from the furnace which are above my garage had much lower airflow and temperature come out.
https://www.amazon.ca/dp/B07VYHVJ28/ref ... FM7D9MSJE1
[OP]
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Nov 28, 2016
18866 posts
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Out west
opendoor wrote: If you're just looking to balance the ducts, a garbage bag and a timer honestly works reasonably well:

http://publications.gc.ca/collections/c ... 09-eng.pdf

I've read you can reliably get within 10% of actual CFM using that method, and my experience matches that.
Thanks. Read that, and while I want to save a few bucks, because of my zoning system, I just want something I can use quickly and get actual numbers from.
Member
Oct 19, 2020
322 posts
189 upvotes
I'm unsure of how much value the tool would be directly for balancing without knowing the heat loss of each room and how much airflow each needs.
It would be useful to determine total cfm going to the vents vs estimated system airflow based on temp rise test, and how it varies as dampers are adjusted, when just one zone is on. Can help determine if you have a major leak.

If you do buy one, look for something that allows you to enter the open area of the vents so it calculates airflow/cfm on the fly.
What an anemometer measures is velocity, not cfm.

This is one of the first on the page that can accept area (it has an area button): https://www.amazon.ca/30-HOLDPEAK-846A- ... ljaz10cnVl

I was looking into buying a multi-meter meter from holdpeak last year, emailed support and they actually answered my questions, which is a good sign. Have no idea if holdpeak is good quality though.
It is a chinese company but even if you buy american, the tools are all made in china anyway.
[OP]
Deal Expert
User avatar
Nov 28, 2016
18866 posts
2427 upvotes
Out west
insertname2020 wrote: I'm unsure of how much value the tool would be directly for balancing without knowing the heat loss of each room and how much airflow each needs.
It would be useful to determine total cfm going to the vents vs estimated system airflow based on temp rise test, and how it varies as dampers are adjusted, when just one zone is on. Can help determine if you have a major leak.

If you do buy one, look for something that allows you to enter the open area of the vents so it calculates airflow/cfm on the fly.
What an anemometer measures is velocity, not cfm.

This is one of the first on the page that can accept area (it has an area button): https://www.amazon.ca/30-HOLDPEAK-846A- ... ljaz10cnVl

I was looking into buying a multi-meter meter from holdpeak last year, emailed support and they actually answered my questions, which is a good sign. Have no idea if holdpeak is good quality though.
It is a chinese company but even if you buy american, the tools are all made in china anyway.
I dont care about heat loss. Ill do these tests winter and summer. I want to test what the airflow is, with even just the fan running. Why throw heat loss in there?

Many people on othger threads want to measure the air coming out of their vents to balance their system.

I want to know what increase in airflow is from the farthest vents, if I close the closest vents to the furnace. And as well test them as zones open and close.

So I go to a vent, do a test, close a vent somewhere else, do a test

Lots of things would be useful, but tell me, as a homeowner how would a person know total cfm going to the vents

You are very helpful. YOu also through in so much stuff to make something simple over complicated

Are you saying airflow on a single stage van varies when heat is called for, and when just the fan is running by itself?

so if I need to measure the airflow from a vent, what tool do I need? Because this is what a search finds me

An anemometer, a test instrument that measures air velocity is used to determine the average air speed in the duct. Then the average feet per minute is multiplied by the area of the duct in square feet to determine the airflow moving through the duct. Traverse the airflow in the exhaust duct.
Member
Oct 19, 2020
322 posts
189 upvotes
The anemometer measures feet per minute; I mainly suggested was that if you get one, better one that can calculate cfm on the fly based on area automatically.

Yes, you can convert to cfm manually.

The anemometer can be very useful for what you want - to experiment and see what closing vents does. But you have no target cfm for each room.

I spoke about heat loss, because for balancing with this tool, you need to know the heat loss of each part of the house as a fraction of total.
This is to actually get the target cfm.
It's a pain and usually adjusting dampers, seeing how the room feels does the job
[OP]
Deal Expert
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Nov 28, 2016
18866 posts
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Out west
insertname2020 wrote: The anemometer measures feet per minute; I mainly suggested was that if you get one, better one that can calculate cfm on the fly based on area automatically.

Yes, you can convert to cfm manually.

The anemometer can be very useful for what you want - to experiment and see what closing vents does. But you have no target cfm for each room.

I spoke about heat loss, because for balancing with this tool, you need to know the heat loss of each part of the house as a fraction of total.
This is to actually get the target cfm.
It's a pain and usually adjusting dampers, seeing how the room feels does the job
My target cfm would be this. All vents open, test. Adjust a vent on that zone, test again, Better than the feel by my hand

Thing is, what if you are balancing for a/c, does that also include heat loss?

All I want to know is what the air increase/decrease is from a vent, thats all. Summer spring fall or winter.

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