It's a good point, but PEX is installed above the sub-floor to circulate the heat and then the mud floor for the tile is installed on top of it. It shouldn't add any height, since the mud floor already has to be 1" to 1-1/2" thick.

a membrane on top of a slope. Good. Summary. Cementing heat cables onto a slab = the heat ends up mostly in the slab (a large heat sponge, heat sink, thermal mass) and some of the heat ends up in the tiles above the cables. The cables distribute the heat 50 50 half going up half going down, but then the warmed up tiles send their heat into both the room and the slab. The slab continues to suck heat out of anything warmer than it, until such time as (theoretically) the slab's temperature matches the other thing warmer than it. (that would be the tile surface). It never happens: the slab just keeps on sucking for ever and ever. The ground underneath the slab sucks heat too. Suffice to say that any membrane will act as a heat transfer slow-down agent, i.e. an insulator and not as a heat transfer conduction agent. if the slab is at a stable temperature, or if its temperature varies with the seasons, it doesn't matter. It's not relevant to the statements in this post.

Yes you can have baseboard radiators and in-floor radiant. "Can they be in the same loop or zone?" That may not be the best way to plumb, as the radiators and in-floor will likely require different water temperatures (supply & return âÂÂT), flow rates and controls. Always use proper design and best practices for assured comfort and reliability, not easiest, quickest, cheapest hookup. Don't forget automatic air elimination and dirt separation. Proper placement of every component is crucial! Plan and document your mechanical room carefully with proper labeling, arrows indicating flow direction, supply & return and a DETAILED schematic that remains on-site and includes every component so that any technician coming on site can understand what they're looking at. HIRE A SERIOUS PROFESSIONAL - you'll be glad you did! IMO SR

If I could add one thing here, as a person who lives in a house with electric baseboard heat: I have found that electric baseboard heaters foster high heat loss, perhaps because they excessively heat the wall above the heater, causing more rapid heat loas to the outdoors. (If my memory of high school science and "Delta T" is accurate.) In addition, following standard HVAC practice they're often placed below windows, further accelerating heat loss for the same reason. Realizing that all electric resistance heat is the same 100 percent efficient (but not cheap, owing to high electric rates compared to other energy sources) this is the only way I can account for the fact that using plug-in electric space heaters (generally fan-forced units) in the house will cause the rooms to be warmer for less energy cost. If this were my house I'd look at the fan-forced electric wall-mount heaters. For one thing they're way faster to warm a room than baseboard, and they're safer than infrared, which operate by design at high temperatures. Plus, putting a infrared heater into a wall kind of defeats its purpose: As they are used to heat objects and people directly, infrared heaters are ideally portable units that you can point in the direction where heat is desired. Having said that, I put an infrared heater in the wall of my bathroom, but that's a small room and there aren't many places you can be. But tell you what, I'd be scared of it in a rental house because if you'd leave a towel or something draped in front of it, that infrared heater could start a fire in no time. Fan-forced wall heaters have limit switches that will shut them off if they're covered. Also, to reply to the above, "quartz technology" would be meaningless in an electric furnace. If you embed the units inside an electric furnace where they're not physically exposed to the people and objects you want to heat, you're just turning them into conventional heating elements that heat air by forced convection. Quartz elements are simply designed to operate at a higher temperature so a higher share of their heat can be given off as radiation. You still get one total watt of heat for every watt of electricity you run through it - it's just that you can direct that watt straight at people and feel warm far sooner, as you have pointed out. By the way this is the fallacy of those costly $200+ heaters that look like wooden boxes. If you stick any kind of element in that heater, or use light bulbs, quartz tubes or whatever, you get the same amount of heat, as any radiation effect of whatever element you use is simply absorbed by the box itself and then convected to the room air the same as any $15 heater from a discount store. Just another option to consider.