I have seen them mounted on roofs , but honestly there are many good air conditioners that do not freeze you if operated properly.

You could check out a heat pump with mini-splits.

"Swamp" coolers don't get a lot of love - for good reason! It'll be a negative if/when you ever come to sell the hosue. Any competent architect can integrate a minimal cooling duct solution in your house. And if you really don't want a traditional split sytem, you could go for a ductless minisplit - expensive, but OK for small jobs.

No more than evaporative equipment cost's I'd use 2 coolers if installing duct is a problem.

I'd get the ducts put in. We have in-floor radiant heat and no duct work so added cooling with ductless mini-split. The ductless mini-split is a nice system but finding professionals to put them in was really hard because they aren't a common technology here in the US. However if you have a professional you trust to put them in then they are great because of the easy zoning and clean operation (no ducts to accumulate dust or blow dust around).

The evaporative cooler that we had before was a pain. You had to winterize it each year and bring it out of hibernation in the spring. But often in Denver we have very hot days and then some more snow. With the ductless minisplit AC we can have AC when we need it in both the spring and fall without having to be clairvoyant about what the weather was going to do.

Another downside, the swamp cooler springs a leak. I had this happen in the apartment in Las Cruces, pita.

The ductless mini-split is a nice system but finding professionals to put them in was really hard because they aren't a common technology here in the US. However if you have a professional you trust to put them in then they are great because of the easy zoning and clean operation (no ducts to accumulate dust or blow dust around).

While this above statement is true in some aspects... there is no such thing as 'easy zoning' or 'clean operation' in the realm of the mini split world.

The refrigerant circuit is zoned in a mini split. This raises technical difficulty at least 10 fold of a ducted zoned system in a world where even a ducted zoned system is rarely installed properly. So because the refrigerant circuit is zoned, each an every time there is a needed repair to that refrigerant circuit you're going to experience a 'gotchya' moment. Refrigerant in these systems is referred to as 'critically charged' meaning the refrigerant must be weighed in. Because of this the mini system can not be 'topped off' with refrigerant. Leaks must be repaired, system charge must be completely removed and new charge must be weighed in once leak(s) are repaired.

Clean operation: all the dust gets sucked into the head(s) of the indoor unit(s). Sure they have filters on them, but the filters are small --- they won't hold much dust. Just don't forget this task the result if you do forget will likely not be a fun experience for you.

Sorry, there is no easy cure for comfort cooling.

I think I wasn't clear. The comment about easy zoning is from the user perspective. Everywhere there is an indoor head you can have a completely different temperature. For us that means only the master bedroom is on at night and we can dial in the temp. we want. We shut the rest of the zones off. My husband can have the temp. he wants in the family room while I can have the temp. I want in the living room (our different TV rooms) etc.

In terms of leak repair we did have it lose charge once on the outdoor unit at the beginning. The guy just tightened the connection where it was leaking and then refilled it. I don't remember it being hard as he had a machine that measured the amount. It was fairly quick. Since then no leaks.

Regarding cleaning the filters. It is the easiest thing in the world. You just take them out and wash them in the sink. We do it at the beginning of the season and then again midway maybe once or twice more depending on the dust accumulation. There is no hidden duct work to fill up with stuff that needs a professional to come clean it out.

We have not yet had to clean the coils. I understand from ionized that it can be a nightmare so we are dreading the day.

When we have had work done in the house we have turned off the systems in the areas being worked on and let the house air out with all windows and doors open while I stayed in the master bedroom with the dogs cool and comfortable. Knowing we weren't sucking any of the dust or fumes into the system.

Is it better than ducted? In some ways yes and in some ways no. But it is cleaner and easier to have zoned temp. in the house.

With a heat pump mini-split I believe you get heat and air.

Yes you do. With ours, once a zone valve on the infloor radiant heat went out in the middle of the night. We could have spent 10 min. replacing it but we were both tired so just turned on the ductless mini-split heat and went back to bed. Then replaced it in the morning with the one from the basement system and ordered a new one for that zone.

mmmm12,

well my thoughts are thru the eyes of a repair man. So I can see how easily I get things confused from your perspective. LOL.

In terms of leak repair we did have it lose charge once on the outdoor unit at the beginning. The guy just tightened the connection where it was leaking and then refilled it. I don't remember it being hard as he had a machine that measured the amount. It was fairly quick. Since then no leaks.

This doesn't surprise me, but if your climate hits extreme temps (hot or cold) this is when improper charge is most apparent, can cause erratic system behavior. Mini splits have all kinds of sensors that will shut system down.

If that happens, the company comes back charges you again for their mistake of not doing it right the first time. Maybe 10% chance he got the charge right doing it this way.

Given my climate, I know better. ;-)

Thankfully hasn't happened, but watch, now that I say that it will happen next year. :-D

Swampers, you either love 'em or hate 'em. Loved mine, roof mounted, in Phoenix. One louvered duct in the main hallway.

Thanks, everyone, this has been really interesting. I confess: I didn't recognize the term 'mini-split' but having looked it up I recognize them from hotels in other countries. I can see that they work really well for some people.

I would say that in our area, swamp coolers are not rare. We're not in a high-end development; it's rural. This house is our retirement destination and I'm not too focused on resale value. That is in fact why I'm quite firm in saying I want an evaporative cooler. For me, swamp cooling in an extremely dry climate is much more comfortable than refrigerated air in a sealed house. I can have my windows open and get fresh air (and should, for the cooler to run efficiently).

In my experience, problems with swamp (evaporative) coolers occur when water lines break and flood. This can happen from lack of maintenance but maybe more often when an uninsulated water pipe or hose running to the cooler freezes and busts the line. The resulting flood - especially on a flat roof - can cause real damage. We will have a pitched, metal roof and will properly insulate the water lines - and keep the cooler maintained, even if that means paying someone to do it when we're too creaky to get up on the roof ourselves.

And I'm still interested in the discussion and your comments! Thanks!

I am not gong to come down in any of the three corners laid out so far, but here are some things to think about. I rented a home in Tucson with a swamp cooler for the entire three+ years I was there. The only time I did not like it was in monsoon season, remember that? Humidity climbs to above 30% and the evap coolers don't work. The heat was forced air. The landlord came in twice a year and moved the "cookie sheets" around in the duct system to convert it from total exhaust swamp cooler to total recirculation furnace. There was a single, central return and I think a supply in each Br, Lr, bath and maybe in the kitchen/Dr area. My memory is that it blew a lot of air to keep the home cool, more than a mechanical cooling system. I could be wrong about that and the air flow required is going to be dependent on the heat gain of the building. I am with you in added humidity to the living space in that climate.

It seems like with your simple home, you may need only two or three supplies. The air will be exhausted directly from each room to the outdoors. You don't need returns. In some areas you should install vents, however, and not rely on windows, for security purposes. Here is an important question for you. What is the water situation where you are building? I think that in Tucson since I was there, water has become tighter making swamp coolers less attractive especially with increased efficiency of mechanical cooling. Please check this out carefully

I am with Elmer and sktn77a with respect to imagination and running ducts in soffits and whatnot. Multi-level ceilings can be very interesting and attractive as well. You don't want your ducts outdoors (vented attic) anyway. Have you lived in a home with a modern cooling system? They are head and shoulders above those installed only a decade or two ago. You don't need any fancy-pants variable speed compressors and blowers for humidity control, but they could make things more comfortable.

In my home, mini splits require a lot of tedious cleaning, but if you need only a couple of them, no biggie. (I have too many at seven in a seven room house.) The house is old and the dirt getting sucked in may be partly a consequence of that. On the up side, I like the way they operate, especially from the humidity control point of view, but that will not be your issue. Note that not all mini splits make hot air. It is an option that adds little cost, but adds mechanical complexity. I had one of three reversal valves fail. Fortunately, it was under warranty. (Note that they first guy on scene was tickled when he tapped on the valve with a screwdriver handle and it temporarily made it go into the heat mode. He said that his teachers in HVAC classes say to do that, but "it never works".)

Is your radiant installer experienced? If not, I'd check into having an outside designer do that part and have the locals install it. It is going to be kind of hard to fix after the concrete is poured. Is this hydronic radiant or are you using electricity? If hydronic, what fuel will you use? Are you gong to use solar thermal to make hot water? (I don't even know if that is economic at this point since PV has become so inexpensive.) Will you be orienting and designing the home based on solar heat gain?

Given your location, the need for humidity added to the air and the common maintenance headache that humidifiers are, the need for cooling only 2-3 months of the year... why not just install a 14 SEER ducted AC with at least one return at the floor location, then get yourself one of these self contained humidifier you could use your duct system as the distribution point by setting your AC fan to on (continuous run).

The humidifier I linked to is rated for 2300 sq ft. Which should easily do the job. The cost is reasonable, when the thing stops working just go out an buy another one. Because maintenance on any humidifier will easily cost you $100 a year or more. Especially after a year of running it non stop. The chore with a self contained unit is having to remember to fill it. So there are trade offs to consider too.

Also by setting the humidifier near the air return of the ducted AC system the noise should be unnoticeable in bedrooms where people are sleeping.

Your climate is perfect for Heat Pump so that is another option open to provide either supplemental heat or back up (economical) heating in the even your other systems go down.

Given what I know from maintenance standpoint this is probably what I would do if I lived in a desert.

I think that you need to consult with professionals in this matter. When I installed a cooling system I asked Fonko for assistance. For economy and ease of use heat pumps are the clear winner. Conventional electric heaters are approximately 3 times more expensive to run than a heat pump and gas heating have negative factors in that it releases harmful gases that can effect those with breathing disorders such as asthma and increases condensation leading to crying windows and mouldy curtains which are expensive to replace. Hope you find my answer informative.

Austin, my assumption, with no data, would be that running a humidifier along with a conventional HVAC cooling system is very counterproductive. The AC would be removing the water as fast as it is added by the humidifier. It would be a costly proposition even if it works. The cooling system would have to be configured very differently in order to spare the humidity in the air while still cooling.

Mia, can you provide details about what harmful gasses would be produced in amounts high enough to affect asthmatics? In addition to that, how does a gas furnace increase indoor condensation?

ionized_gw sorry but I am not specialist in such cases

Austin, my assumption, with no data, would be that running a humidifier along with a conventional HVAC cooling system is very counterproductive.

It is, but this is for desert / arid climate. While you can argue that AC dehumidifies, it is run / operated via temperature control. Humidity as you know is independent from temperature.

This arid / desert climate is probably just as complicated problem to have as removing humidity in my climate. A typical AC design doesn't remove enough on it's own in my climate. You need the humidity in an arid / desert climate to feel comfortable... so what do you do?

We also live in NM and used to be at the same elevation you mentioned. My husband also hates AC and we had an evap cooler then. My main problem with it was the dust. It was nice to get in the fresh air, but I was spending all my free time dusting. However, it was very economical to run.

I grew up in Phoenix and lived in Tucson for about 10 years. In Phoenix you absolutely need regular central air and heat for comfort. Its just too dang hot for a swamp cooler to work. And that's dry heat. Tucson is at a slightly higher elevation and doesn't get quite as hot. I had a window swamp cooler in a tiny house there, but there were days when it just didn't work; either too hot or too humid. It wasn't a huge deal at the time, I was young, I was renting, I worked during the days. But in a retirement home, where you might be spending more time in the home, I would def go for maximum comfort. If you got a heat pump, you would have air and heat without a furnace. You can use a heat pump with ducts or mini-splits. You wouldn't need radiant heat or a wood stove. The heat pump can be installed outside like regular ac with splitters that come through the wall in each room and use wall mounted boxes. In a house like you are designing for ductless, you would probably need three boxes. Another advantage, is that you can turn off the boxes in rooms you are not using so you don't always need to cool or heat the entire house. For example, at night when sleeping, you could just use the box in the bedroom. Once up, you could just use the living area. You wouldn't need to use the box in the second bedroom unless you had guests. I think a heat pump with splitters is more expensive to purchase, but it the long run, it would save on electricity. A heat pump with ducts would be ideal, but you wouldn't be able to turn off the boxes in individual spaces.

Mia, the information that you posted about gasses and condensation is misleading at best according to my understanding. If your knowledge is limited, perhaps you should stick to your specialty.

The OP is proposing to install hydronic, radiant heat. Although heat pumps that make hot water are available, they are unusual in an air to water application. More usual has been hydronic heat with earth-source heat pumps. The demand for air to water heat pumps is pretty low so costs are probably quite high due to diseconomies of scale.

Austin, the problem as I see it is that mechanical cooling systems are designed to cool and remove humidity. I've just never seen a system that is designed to add humidity coupled with that. It would have to be done right to prevent adding humidity only to tax the mechanical system to remove it adding a lot of cost to running it. My experience in Tucson was relatively short and a long time ago at 20 to 25 years ago. Things may have changed, but I never heard of anyone running a swamp cooler in conjunction with conventional mechanical air conditioning. My memory may be faulty, but I think that humidity there was typically below 10%, but ranged up into the 30s during the summer rains. In addition, the swamp cooler raises the 10% humidity to somewhere in the 30s on hot days. At that point, the cooling is not sufficient.

A conventional AC system will probably be removing only heat and not humidity at 30% RH, but I don't know for sure. If so, a well-controlled swamp cooler could work in conjunction with a well, controlled mechanical cooling system that is biased to removal of sensible heat and removal of no latent heat. Has anyone tried to engineer a combined system? I'd love to see the results if it has been approached in any way.

I've never seen or heard of anyone trying to add humidity to air cooled using phase transitions of compressed refrigerant gasses in my time there.

suzyq53, evaporative cooling won't fail to keep a home sufficient cool because it is too hot outside, it will fail because the evaporative cooler is too small, the capacity does not match the load. They do fail when the humidity gets too high.

I think that you miss the OPs point. They certainly don't "need radiant heat". They WANT radiant heat. If you've ever experienced it, you may not understand. it us superbly comfortable.

Note that in a new, well designed and constructed home, heat and humidity transfer from room to room is very high compared to heat transfer with the outdoors. Zoning won't save you much money in that situation. You might want it for comfort.

cooper8828, Was the dust in your previous experience from the outdoor
air or from minerals in the water? Perhaps a well-placed and
properly-chosen filter would solve that problem.

ionized_gw,

I was at a home recently (few months ago near Katy,Tx) that has a whole house humidifier that is a self contained unit attached to the furnace via a hose. It was only at best a few years old and not working which is why I say you never stop paying for a humidifier.

Anyway, in my opinion it's counter productive for my climate as it's almost always too humid here. The home owner in the above instance says he has it shut off except for in the winter which is typically at best 2 months long here.

Typically a humidifier in this instance above is run via a humidistat. It's not run via a temperature controlled thermostat.

Here is an example of what I am talking about