Lissa- I just had a Franke Little Butler installed three days ago and I can't tell you how much we love it. The reason I chose it was that I wanted both the hot and cold water to be filtered, and at the time I was looking, Franke was the only company that did this that I found. (I bought the unit last year, yes it has taken THAT LONG to get to where we were ready to install it). The Insta-hot brand filtered the cold but not the hot water. Anyway, the unit is not that big-- the heater is a rectangular cube about 11x7 inches. The filter (it is a Franke triflow filtration unit) is a cylinder about 11 inches high by 2 inches in diameter. However, I don't have a separate cooling unit for the cold water, since the temp coming out of the cold tap is good enuf for me. Also, my fridge has filtered cold water for those times when it matters to me. But the Little Butler filter, heater, and my garburetor fit very comfortably in the sink cab, which is 36" wide. As for cost, when I was looking these units were quite high, but I bought mine from an ebay storefront with 100% positive feedback for about half the price I was quoted in the snazzy plumbing showroom (can't remember numbers now, it's been so long). Hope this info is of use, good luck!

I am researching this topic myself. I realize this is months after your question. But insinkerator instant hot has a faucet with instant hot and cold, and it can be filtered or not. There are 2 handles on 1 faucet. My plumber recommended this brand. I have no financial ties or personal experience with the unit.

Waterstone and Dornbracht both make two handed faucets for hot and cold water dispensing. Mountain plumbing is another option to look at. Your link to Westbrass did not come through Good luck!

Your builder is handing you a lot of BS there. These units are never considered a “necessary” luxury. Do you have the Sub Zero refrigerator? Pro style range? In some locations, those would be considered necessary at a certain level of build. A hot water dispenser? Ah, nope. Having had had one prior, it didn’t make it to the next kitchen. When you find yourself making excuses to use it, and those excuses are few and far between? Plus, to make tea, you want fresh oxygenated water heated to just shy of the boiling point for the best flavor. A freshly filled electric kettle is as rapid as happens for a pot of tea. For a cup, the microwave is the quick solution. Now, I collect tea pots, and have a whole cupboard of different teas, so someone who isn’t as fussy about it could be perfectly fine with an instant hot. I put that instant hot money into a whole house tankless water heater.