With two separate thermostats and two different rooms, I'd prefer to see a setup like the one below. It's certainly not the only way to do it. But it's fairly simple: Hopefully you can sort of reconcile what you have with the bits and pieces in the schematic. Again, you might not have all of them, or you might have more. And the bits and pieces don't have to be in the order or in the locations I have them. I'll start by writing about the shutoff valves. There are several in the schematic. They bracket some of the bits and pieces to allow maintenance on your system. Example, if you have to replace a pump, you can isolate the pump by turning off the shutoff valves on either side of the pump. If you have no shutoff valves, when you pulled the pump out of the loop, you'd lose all the water in your system. I prefer full port valves for shutoff. The photos are just for reference: So you have the water heater. Hot water comes out of the water heater and flows through a check valve. That valve prevents backflow or reverse flow through the water heater. Typical backflow valve: The pressure gauge allows you to monitor the pressure of the water in the system. I usually run closed systems at about 12psi of water pressure. After the pressure gauge is a "fill" hose bib. Just like a garden faucet hose bib, though you can certainly use something better. There's normally a hose connection down low on the water heater. You connect a garden hose to the water heater bib, open the "fill" hose bib, and fill the system with water. Or a water/glycol solution if you need freeze protection. After the fill bib is the expansion tank and the air eliminator. Since it's a closed system and water expands when hot and contracts when cool, the expansion tank allows the system to absorb those changes in water volume while allowing the system pressure to remain constant as 12psi. Expansion tank: Air eliminators have a couple of different looks: or this: To the right of the expansion tank is another "fill" valve that has a cold water supply plumbed into it. That's a pressure compensating valve set at, you guessed it, 12psi. If the system pressure drops below 12psi, that valve automatically opens and recharges the system to 12psi. The little lever on top allows you to add water manually. The valves are usually pressure-adjustable. I just happen to use 12psi as my setting. Why would you need to add water to a closed system? The air eliminator "burps" air from the system. Air in the system can cause turbulence noise when the water flows, a large bubble could cause flow problems or pump problems. So the air eliminator eliminates air. But sometimes water can dribble out too. So if/when you have water loss, the 12psi valve will recharge the loops with water. The "Temp in" gauge shows the water temp as it enters the loops. Usually about 120 degrees. Maybe more or less. Then the system branches off into two zones, one for the bathroom, one for the sunroom. Each zone has its own circulating pump. When the room's thermostat calls for heat, the circulating pump kicks on and circulates hot water through the zone and to the loops in the zone. Typical Taco pump: You can add a Grundfos Alpha pump. Very energy efficient: With two pumps, the rooms can be heated individually or concurrently. When the water returns from the zone(s), it goes through another temperature gauge. You can compare the Delta T or the change in temp of the water to see if the heat is being given up to the rooms. "Temp In" minus "Temp Out" equals Delta T. And there you go. Again, each zone can simply be a single loop of PEX. Small rooms can sometimes be served by a single loop that is on it's own zone. If the room is large and you need more PEX, then you can install a manifold for that zone and you can have several loops on that manifold. Again, each loop should only have about 225' maximum of tubing in the loop. If a room needed 350' of tubing, I'd split it into two loops of 175' each instead of a 225' loop and a 125' loop. Example of a four loop manifold, this manifold has the "temp in" and "temp out" gauges built in: That's a basic system with no real automation.

Yes, appears to be communication issue with contractor. Contract says in open beams above garage which is basically half of the floor. At the time, I was not familiar with this type of system, so I had no clue what it even looked like, the contractor knew we wanted all of the walking areas heated since my first request was to use electric pads in the walking area and he talked me out of that and said just create a separate zone off of your furnace for the kitchen floor. Not a big deal to finish it, half of the remaining floor is open beams in laundry room, and the rest is in ceiling above a bathrrom which I'm fine with them taking out the ceiling and replacing with drywall.

gbsim Your house with real wood trim, moulding and doors look very lovely, warm and grounded. Don't let anyone paint that beautiful wood trim in awful contractor special white that looks shiny and tacky at the same time. I am so tired of looking at cheaply done MDF shiny white trim on so many houses that it is a breath of fresh air to see real wood trim and moulding. Not only does the MDF and bad paint job make the trim look shiny, most people end up picking stark white that makes the trim look like pimples with make up on it. Coupled with strong paint color on the walls, whew! Good luck selling your house! It really has kept its age well. I know what you are talking about: the unknown construction quality. We have gutted and redid our house. There is nothing left of the original house. We can't imagine not knowing how things were done behind the walls. My husband even had them put metal flashing between each joins of the lap siding! (kind of extreme but...) We have a walk out basement: we call it daylight basement here. They don't live like basemnet at all. I suggest exploring in floor hydronic heating for the basement slab. It is expensive but it makes the basement quite comfortable.

You say that energy efficiency is important to you. Resistive electric heat of any kind is about as INefficient as heat gets. Doesn't matter whether it's radiant panels or baseboard units or a portable space heater or an oil filled radiator or your carpet pads. They all produce heat exactly the same way. They all will cost exactly the same amount to heat a room to the same measured temperature. They all are equally inefficient. Now, the heater manufacturers will tell you that their heaters are 100% efficient. And they are. They turn 100% of the electricity coming into them into heat. However, the process that makes the electricity is not 100% efficient. Many power plants burn coal or natural gas. A coal plant typically converts about 35% of the coal's energy into electricity. Usually the remaining 65% goes up the stack as waste heat - heating the outdoors. A natural gas plant is a bit more efficient, typically 50% IIRC (I'm sure someone will correct me if these numbers are outdated or I'm remembering them wrong). Newer power plants better these numbers, especially cogeneration plants where they make use of the waste heat, but they still don't get to 100% or even 90%. And then there is further loss in the transmission lines to your home. So which would you rather do? Heat your house with half of the energy in a cubic foot of natural gas, or heat it with nine-tenths of that energy? A good forced air gas furnace can easily be 95-96% efficient. Even a cheap one is 80% efficient. No contest. A natural gas fired hydronic heating system is just as cozy on the feet as your carpet pads. It may not be quite as efficient as a forced air system (depends on installation) but will still easily be in the 80% range or better. Circumstances can alter the equation, of course. Maybe your electricity is generated not from coal or gas, but from falling water (hydropower) or even wind or solar sources. (We won't discuss nuclear energy so as to not "generate" controversy over that.) Or maybe you don't have natural gas service where you live. That leaves LP gas, coal, wood, and a few other fuels. In a sunny region, solar heating may even be viable for part of your heating needs. And of course there's electric heat. The most efficient electric heat choice might depend on where you live. In cold climates, the most efficient electric heat system is a ground source heat pump ("geothermal" heat). It draws heat from the earth. By the "100% efficient" standard of a baseboard heater maker, a GSHP is typically 350% efficient! That is, 1 kWh of electricity gives you as much heat as 3.5 kWh in a carpet pad like you are considering. The downside of a GSHP is usually a relatively high cost of installation. In a very mild climate, an air exchange heat pump will have almost as good a coefficient of performance (COP) as the GSHP. The colder it gets, the less efficient a conventional heat pump is. As you get close to 0 deg F an air heat pump drops to about the efficiency of baseboard heat or your carpet pads. A conventional heat pump is more costly to install than baseboards or carpet pads, but less than a GSHP. This is really just a start, and we're getting off topic here. I suggest you take this discussion over to the HVAC forum.