"That means he could twist his words after executed the contract with me?" If you were buying a new Honda Accord, would you accept that no specific model number was put on the sales contract (ex. LX, EX, EX-L, 4 or 6 cylinder)? It is the same thing in HVAC equipment. You are paying for a specific size and model for each piece equipment. Perhaps you trust the HVAC contractor to do the right thing, but more often than not it does not happen. If you have low humidity (less than 30%) then you may want to invest in a humidifier, otherwise you don't need.

WHAT IS A HIGH LIMIT SWITCH? https://www.newcentralairconditioner.com/ The high limit switch in your gas furnace is a small part with two very important jobs. This switch plays a role in the normal operation of your furnace. Turning the fan motor on and off is the high limit switch’s main job. This is the role it plays in every cycle of your furnace’s normal operation. But that’s not the only thing that the high limit switch does. It’s also safety device that helps prevent your furnace from overheating. The high limit switch consists of a long temperature-sensing probe attached to a metal mounting plate. From the mounting plate, the switch is wired to the blower fan motor and to the gas valve. The switch is generally located just past the heat exchanger. This is so that it can detect the temperature of the supply air. In other words, the air that’s about to be blown into your home.

The biggest problem with HVAC zone systems is knowing when to choose it as a solution and when not to. Some HVAC companies it's about "sell, sell, sell" whether or not it works... there's more money in "sell, sell, sell" --- when it's only about money? So does the comment above mean I do it for free? No. If you think that you are reading things that aren't there. New construction? best to choose separate systems 9 times out of 10. In order for a zone system to work, you have to know what you are doing. Most HVAC companies staff (the techs they send you) are 20-30 year olds. How much practical experience could they possible have? It's best for HVAC zone systems to be an elegant solution. A HVAC zone system is a tool in the tool bag. Not all homes are suitable for zone systems. Some homes there is no other way, and in some cases complications to those problems will make an HVAC zone system design possibly more prone to problems. You have a problem now, do you want more problems. These decisions among others are decided "in person" --- so considering that becareful what information you decide upon from the internet. Just because it's here doesn't necessarily mean it's true. That said: Depending on equipment level chosen, how many different floors you have in your structure, how much room you have available... will all be factors that make you decide one way or another. From there it's in your best interest to pick a contractor that is skilled: especially when it comes to HVAC zone systems. (there's a lot of garbage out there.) (click to enlarge if necessary) I service the Katy, Texas area.

@booty bums See here to respond to the questions you bring up. @Seabornman That's exactly true here, too (another NE state) on the solar. Just so folks who aren't familiar understand how this works. It's called "net metering". I live in one of the darkest states in the country, but the sunnier months produce excess electricity. This goes on the grid, and I get credits for it that I use in the winter. As I mentioned, I have NO heat bill. I actually have no electric bill year round. My house is all-electric. This also means the electric company doesn't have to buy (expensive) electricity; instead, it can use the excess electricity coming from folks' solar panels. This keeps prices down for everyone on the grid. IMO Most anyone with a home would want to check to see if there's net metering in their state. You might pay off solar panels way faster than you think. For instance, are you paying $500/month for heating or cooling as many people do around here? Also, if you can't do solar panels (maybe your house is in the shade), in some states there's community solar. You buy into it. The panels around here are in old meadows and landfills, generally out of sight. I'm guessing excess energy from any alternative source could be uploaded to the grid. I had thought of using a windmill in winter! But I'm not sure how my electric company handles this. IMO every state should have the net metering option or get them legislated ASAP. Soon solar (or another alternative energy source) will be essential for selling a house. ****** Incidentally, my state also audits the "tightness" in your home. There are extra incentives that go along with this. ***** Footnote: while the netZero set up in my home might sound complex, it's actually very simple. Just clever. Basically: 10" thick walls, energy-saving materials like double-paned windows, solar, shed roof, CERV, heat pump. Habitat for Humanity is building houses like this around here; it is LESS EXPENSIVE than what they otherwise build.