George Wenzel wrote:

In article , C G
says...
Don't worry much, that was just the rantings of a "pro" who has been
conditioned to disparage anything a DIYer might use. It helps them
protect their markups.

Perhaps. I just had a humidifier installed on my furnace, and the
installer mentioned that they had a thermostat/humidistat made by Lennox
that could control everything in one place. Thankfully they weren't at
all pushy in recommending it - they only mentioned that it was available.
I nearly crapped my pants when they said it cost $450CDN.

I think I'll stick with the $45CDN Lux that I bought at Home Depot. It
seems to be working just fine for me. :-)

And even if it dies in a couple years, you can replace it 9 times before
you get to the price of that wonderstat recommended by your installer.