John E Davies Posted February 14 Share Posted February 14 I have been really mad at how noisy my furnace is, it drives one of my dogs completely nuts. I plan to do an extensive thread on the changes, but I am not done yet, and I have some return airflow testing to do using HVAC smoke matches. I used a free sound meter app on my iPhone 13 Mini, so the actual numbers are probably not real accurate. I used these settings: I set my iPhone on the street side bed platform with the mic facing the furnace grill, and I put the two fiberglass access covers and the mattress in place over the furnace. (10” thick optional mattress.) I started recording, walked to the thermostat, started the furnace, let it run for about a minute, then let it shut off automatically before turning off the recording. There were no extraneous outside noises, the test was done inside my RV garage. Here is the initial test: Here is the final test: Before the mods, the furnace was irritating and screechy. Afterwards, it sounded a little quieter, but more importantly, it was much more even and mellow. I am nor sure how to interpret the graphs, but it appears that the peak red sound levels (dBa) are reduced, and the peak blue max frequencies are HUGELY affected, the peaks drop from 3000 hz all the way down to 300 hz. (!!!) And the green average sound level goes from a crazy pattern to a mellow even one, way lower…. I think that change is what I am hearing. My dog will like it. Comments welcome, especially from an engineer. FYI, if you want to get a feel for how much nicer it can be, find a high density foam pillow and stuff it hard over your return air grill. My mods are quieter… John Davies Spokane WA 2 "Mouse": 2017 Legacy Elite II NARV (Not An RV) Two Beds, Hull Number 218, See my HOW TO threads: https://olivertraveltrailers.com/topic/john-e-davies-how-to-threads-and-tech-articles-links/ Tow Vehicle: 2013 Land Cruiser 200, 33" LT tires, airbags, Safari snorkel. Link to comment Share on other sites More sharing options...
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!Register a new account
Already have an account? Sign in here.Sign In Now