A mini-split system sounds like a good idea, but I still always prefer central air. Here's why: constant, whole-home air circulation (if desire), and you have allergies so if you have an air filter (media, electronic or HEPA), this could help; and more even temperature throughout the home (with a variable speed blower). Sometimes this is cost prohibitive and not feasible. If the contractors you visited with (I don't know if you just talked to them via phone or they visited actually) recommended this, I'm assuming they have a "plan" in mind. Sometimes it's difficult to retrofit, sometimes it's not that big of a problem. A mini-split sounds like a feasible option, but do you really want to see them hanging on the wall? Some people don't mind them, others don't like them. :) I wouldn't worry about air handlers leaking in the attic--that's what an emergency drain pain is for. If water begins to fill into it due to a clog in the main line, it is piped outside where you can see the water. There are also emergency cutoff switches should there be water in the emergency drain pain. Call a couple more contractors for their opinion and get an idea of prices. Hope this helps.

Finding a ductless split that doesnÂt use wireless infrared communication with a remote stat or DDC type communication with a wall stat, is just about impossible. The major reason for this is most are manufactured or was at least designed overseas, thus the technology. I can think of one company, EMI by ECR Int. with some US roots, located in central NY that has AC/HP wall units that can still use a remote wired wall stat that should give you the contacts/points to control operation with a main control interface. Here is a link that might be useful: EMI

The rebates and conservation programs are almost always mandated by the governing public utility oversight boards, not originated by the power companies. The power companies would prefer everyone heat with electric resistance heat and use incandescent bulbs, the more the better. Nothing wrong with that, it's their business to sell power. However with cheap gas nationwide (other than in PG&E territory) and electricity prices that will only rise steeply (as coal and nukes are phased out and costs from building new renewable sources come in ), gas remains the best choice and the cheapest way to heat homes. In any area where natural gas is available, the cost comparison is a no-brainer. In the mild winters areas of most of the West, heating using hot water, in whatever form, is rare and hard to add as a retrofit. It has never caught on. What remains is ducted forced-air gas furnaces. The ducts then serve for air conditioning. The term inertia refers to the tendency of a something's state to continue unchanged, whether that's the state of motion or the state of rest. Around here, the minisplit business has no perceivable movement and I don't see that changing.

OK, lets go at it piecemeal. What is the width of the range? Is it electric coil, gas, or induction? If installed, or if there is a fixed installation plan, what is the spacing of the upper cabinets on the sides of the range? With respect to air flow: There are several commonly used rules of thumb, one of which is based on total potential BTUs. The BTU method is an indirect method of estimation of needed flow rate, and doesn't account for how well the hood overlaps the range. I prefer the more physical approach based on the needs of capture and containment (what hoods are supposed to do). Capture efficiency depend on how well the hood aperture overlaps the rising and expanding cooking plume (effluent). Containment efficiency is determined by how well the hood air flow through its baffles (or mesh filters) keeps the plume from reflecting out of the hood when it hits the sheet metal baffles or mesh structures. A generally sufficient air velocity is 90 ft/min for gas cooking; induction cooking may allow one to get away with a bit less as it doesn't have a gas combustion plume adding velocity to the cooking plume. Electric coil plume velocities may be in between; the lab measurements that I've seen published don't include coil cooking measurements. (Gas cooking can cause the central part of the rising plume to reach 1.2 m/s.) The necessary air velocity has to exist over the entire hood aperture; we don't get to block off portions of the aperture that we are not cooking under. The aperture has some area -- more if there is good overlap of the plume expansion. Hence I suggest 90 CFM/square foot of aperture to get 90 ft/min everywhere. (You may notice that this is about half of the uprising velocity. We don't need to equal it, only keep it from reversing while the baffle aerodynamics take control of it. Baffle design and mesh flow effects may vary how well a given average air velocity works. I know that around 90 ft/min works for me when induction wok cooking, and that Greenheck suggests for similar cooking a value of 85 ft/min for their commercial hoods. There are types of commercial cooking that call for considerably more velocity, such as grilling, but this is not in the scope of our present discussion.) Ideally, to get good capture to make use of this containment, the hood has to overlap the locus of hot pan bases by about 10 degrees half angle. From this another rule of thumb has arisen that suggests overlapping the cooktop by 3 inches on the sides and front. This overlap is probably too optimistic for some searing or wokking, but many here have reported good capture with this size. For a 30-inch range, this would require a 36-inch wide by 27-inch deep hood. You may not have room for this, or you may wish to depend on the side cabinets to channel the effluent from rear burners and cook the greasiest stuff there. So for a 30-inch range, the minimum hood would probably be 30 inches wide by 24 inches deep (front to back). I suspect for most 20 inches deep is too short. As you may appreciate, the larger hood thus has higher total air flow requirements than the smaller hood, costs more, and requires more make-up air. So you may also appreciate that this aspect of performance alone is in conflict with affordability for a given level of aesthetic design. Wait until we get into make-up air issues. kas