How to have a quiet furnace???

Kungur · Post by **Kungur** » Sun. Mar. 17, 2019 8:06 am

Currently we have a KA2 with radiant floor heat and quite like it. But we do suffer from a dry house. We do have a gas furnace that is used during the shoulder seasons and for cooling. But we really do not like hearing the blower.
So here is a crazy idea! Is it possible to have some type of air handler, with a large volume cfm blower that runs slower and will move a lot of air. Of course this would require a heat exchanger.
So looking to the "brain trust" for thoughts!
Thanks!!

coalkirk · Post by **coalkirk** » Sun. Mar. 17, 2019 8:48 am

Most modern equipment has a way to adjust the CFM of the fan. I use a Trane air handler and have the fan running 24/7 at a low speed. I do that for two reasons. It evens out the temperatures between the 3 levels I'm heating and I'm using a central humidifier. If there is a heat call the fan ramps up to a higher CFM. How quiet it is has a lot to do with the design of the duct system. I have a return in every room. If a system has one big return on each level its going to be quite a bit louder.

franpipeman · Post by **franpipeman** » Sun. Mar. 17, 2019 6:01 pm

Noise is relative to duct size . To reduce noise one must have duct sized so that the cubic feet per minute required does not have a velocity or speed that makes noise rushing through the duct and grills and diffuser . It your ducts are not sized properly , noise may be inescapable in order to stay warm or cool.

hotblast1357 · Post by **hotblast1357** » Mon. Mar. 18, 2019 5:44 am

Proper duct size x3! And a properly sized cold air return!!!

The only way I know my furnace fan is on is if I look that the tstat.

Kungur · Post by **Kungur** » Mon. Mar. 18, 2019 7:43 am

Interesting comments about duct size. So are you talking about the main lines only? Because there is 6" round branching off the mains to the registers.
Thanks

franpipeman · Post by **franpipeman** » Mon. Mar. 18, 2019 9:40 am

Having a quiet system is wonderful.I built one in my daughters house. In residential homes historically duct size was determined by how much space is there rather than what size do i need to install. Consequently it could be very difficulty to achieve a quiet system by retrofitting or rebuilding the ductwork due to size . Some residential systems dont have any return lines and that may be the place to start if you cant do anything else. In reality you should do a heat loss study to each room then determine what size supply and return is required for each room and try to build accordingly. Heat loss formulae can be found on the web. Or a knowledge HVAC person could wing it especially if some the system is acceptable. a link to a basic system below

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&s ... 2734601016

McGiever · Post by **McGiever** » Mon. Mar. 18, 2019 12:17 pm

With competitive bids and lowest bid likely getting the job, guess how the job turns out????

The wise owner or builder has all bidders bid the same specifications...apples to apples that way and no halfazz job.