Bought a decent sized evap and R/C unit. Also have a heap of ducting.
Looking at having both options for cost reduction.
Wondering who has both? Any issues? Did you use completely seperate ducting? Or use a zone damper / day night system to easily chose between the two?
Cheers
I'm looking at keeping it reasonably simple. Some evap ducts will be totally seperate (400s to kitchen/ lounge), but share the 300 ducting to bedrooms (so only 1 outlet on the ceiling keeping it neat), then a couple of 450s to the central passage area for bulk evap flow (using the air intake box for the RC as a large outlet for the evap). Damper / ysplits to close off the evap when not in use. The evap unit itself has a flap at the bottom that requires air flow to blow open. So will close off to outside air when not running anyway.
My main concern is any issues with moist air potentially blowing into the return air side of the RC?
Sounds complex, there’s nothing simple about this. Using the return air grille of your RC for evap and running the evap through your RC components sounds like a disaster. I would suggest drawing a diagram of what you’re planning and find an AC installer or mechanical engineer to have a look at it for you.
Cheers, yeah I have done just that with Air Diffusion and a couple of installers. Not sure how much air would pass through the indoor unit (no fans spinning). Obviously both would never run at the same time. But so far, all installers said there would be no issue with the moist air blowing on to the indoor unit (but I guess they are in the game of installing new units ;). But I would need to make sure the air entering that area is filtered. Not sure if the wet pads themselves would be considered a sufficient filter.
Hmm, I have enough spare vents/ Return boxes, I might keep them seperate to rule out any risk of stuffing up the indoor RC unit.
Just out of an FYI - Most said the different vent placement between the 2 systems is the biggest issue. However, mine are all smack bang in the middle of rooms, so hedging bets already anyway. The consensus is it will work well, but no one does it (due to cost of buying the units, and most just pay the premium for running RC)…but this is Ozbargain!
Cheers for the feedback
Surely buying two units, and having them installed, ends up costing way more than just paying a bit more in electricity for the reverse cycle? Just stick solar on if you are that worried.
I kept an eye out over winter for ACs. Picked up a near new Breezair evap unit for $100, and a 14kw Fujitsu inverter system for $350 (from demolition houses on gumtree). Inc full ducting for both, 9 zone motors, 3 day/night motors. Plus, house currently has a ducted setup already in place (with a dead RC unit). So no shortage of gear!
I'll mod the ducting, so the install isn't that expensive.
Also got 3kw solar. Don't know why manufacturers don't just make a hybrid system. Seems logical to me. Both have their perks and limitations.
Seriously, just forget about evap (its pretty crap anyway) and get the r/c unit. A good quality unit would be quite efficient and would really not cost so much more on your monthly bill.
Being crap is debatable but yeah, if you get worried about the amount of electricity the RC is using just install solar - it would be generating peak power when you really need it, when it is sunniest and hottest. I love my evaporative system but if I was buying a new house with no cooling yet I would go RC.
Evap starts being effective if relative humidity is under 50% and gets more effective the lower it is. They're completely ineffective in high RH areas.
It costs much less than air con to run assuming the RH is appropriate.
Mostly dry heat here. Evaps work well, I prefer it. Using the delta T on the BOM observations let's you know what temps the evap will get down to. Also looking to eventually have open bifold doors. So definitely want evap on open door days.
RC will be for humid days and in winter for heating.
Surprised more people dont have both systems.
Surprised why people still buy Evaporative.
@boomramada: Can you elaborate?
From my perspective
Cons:
Less than useless on humid days, may induce indoor mould?, some maintenance of pads, dump valves etc required, possible bush fire and break in entry location / risk.
Pros
Works really well in some places, running costs are basically a fan and lifting a small amount of water 3 feet, no 'dry out' issues (some skin conditions, indoor plants etc), no circulating cold n flu bugs, work even better when you open up spaces (ie outdoor/ indoor open living).
Never had it, but alway impressed by neighbouring evap systems, and they love them.
??
@tunzafun001: I agree that evap cooling is not such a bad idea in drier climates.
w.r.t disadvantages, this lists almost all of it.
Btw, RC does recycle the air but thats not a bad thing for those with pollen allergies and stuff.
We had our ducted heater replaced and the guy said don’t bother getting the dual ac+ heater, ends up costing way more then if you have rc or evap
Heated gas you mean? if so, yeah definitely pass.
Evap opens up lots of extra holes in your roof which will require more heating energy in winter. I've just got one 9kW split system in the main lounge in a 300sqm house with electric underfloor heating in bedrooms and bathrooms (winter only) and I'm in t-shirt and bare feet all year round. (Ceiling fans in bedrooms too). 8-star rated house. Power bill is only about $2200 for the year. Mainly dry clothes with dryer, have a pool, two fridges, and 5kW of solar on the roof and no gas connection.
I think the holes hypothesis is a bit of a myth. With the dampers shutting off the duct outlets (plus you can obviously close the stand alone evap ducts entirely in winter at the facia), I cant see it being an issue. I think the duct work (with trapped air inside) will actually be extra insulation. As for under floor heating, that would be quite inefficient compared to RC (more a luxury thing I guess). Im aiming for a zero electricity bill for 2 people with a 3kw solar system (probably need to upgrade it to 6kw). The last 12 months our total bills were around $200, using an old wall air conditioner and ceiling fans in bedrooms. Looking for a little more comfort, but around same cost. I think evap could do that. Our North aspect doesn't require much heating in winter. Our house is 60s built, so definitely not 8 star (double brick, no insulation in walls..other than the layer of bricks).
Just out of interest, why do you use a dryer? Never owned one and never felt like I needed one (in southern Australia)? It would make up a large part of your $2200 and eco foot print.
RC uses much smaller ducts and registers than Evap, and even if you could share the ducting the coordination of the integration of two systems would take some quite a big of engineering and know-how. You're better off looking at this as two different systems.