Home AC always running

[I_Want_My_HDTV]

Alcohol, in particular, can cause excessive sweating. No doubt, foods or drinks high in sugar could do the same since they the body must metabolize the sugar, which is high in energy. Certain health conditions and medications can also cause the same problem. OTOH, some people just sweat more or have different comfort levels.

If furnace fan circulation is used, a thermostat that has an intermittent and/or programmable fan option can be beneficial. That way, the fan can be set to run only part of the time and/or when it is most beneficial. Furnace fans consume energy which costs money and is converted into heat. It makes no sense to run the fan when nobody is home or when it provides little improvement in comfort levels.

[Jake]

Mind if I step in with my question?

I have a Nortron electric furnace with a York HBBA F030SE air conditioner and Freshvent 1001DXB air exchanger. The air exchanger has 2 intakes and two returns. On the furnace there are three sets of toggle buttons. They are,

Fan: AUTO | ON
Energy Saver: Mild Weather |Cold Weather
Summer Switch: Ventilation | Heating

On the wall the dehumidistat has,

A toggle for: small fan icon |large fan icon
A toggle for: House icon | House icon with in/out arrows
Plus a dial for the comfort zone (50 - 30).

On the furnace control There is another AUTO | ON control along with the HEAT | OFF | COOL switch.

My question is what is the best combination of settings for summer. I googled air exchanger settings and got just about every possible combination.

I have furnace control set to AUTO and COOL to 23 and fall back a few degrees during the day. In the basement registers are closed as it stays about 19 degrees down there.

[TKG26]

You got lots of combos enough to confuse most of us. Unfortunately each product comes with its own features and switches that sometimes duplicate what others can do.... Mixing of brands adds to the confusion.... Right now the industry is changing. Carrier,Lennox and Train have products out now that talk to each other via data and a central thermostat(looks like PDA in some cases) It's all getting smarter and similar to commercial... In comercial setups when outdoor air is low in temp and humidity the ducts open to let that in to kool the building instead of the cooling system.. we are not quite there residentially..

Anyway ill try to pick apart your system based on what you posted:

Nortron electric furnace
Fan: AUTO | ON
Energy Saver: Mild Weather |Cold Weather
Summer Switch: Ventilation | Heating

Electric furnace is a heat only product they don't come wired for cooling a fan center gets installed to retrofit these to run A/C
-Fan, This is likely your fan limit control. Usually has 90-250F dial on it ON=runs 24/7 AUTO=runs when heat is on only
-Energy Saver likely refers the the banks of electric heating elements. Kind of a manual multi stage affair where you select the stage necessary(2 stage heating stat is what we use on natural gas)
-This is a manual fan on switch or running the fan 24/7 and in auto in the winter again a duplicate of the first Fan limit switch

On the wall the dehumidistat has,

A toggle for: small fan icon |large fan icon
A toggle for: House icon | House icon with in/out arrows
Plus a dial for the comfort zone (50 - 30).

This would be tied to your heat recovery ventilator and sometimes your furnace fan. You got fan speed hi and low, then i think continuous circulation without outside air, and then air exchange mod with the arrows in and out. The comfort zone in the summer should be set for 30% we don't want humidity. Its pretty safe in Ontario that you will always exceed 30% humidity so keep the dial low.
Depending on the way this thing is wired or setup and keeping cost of hydro out of it. We will just think comfort. I would run the large fan icon, set to 30% and set the house icon to in out arrows only when the outdoor temps are low and humidity levels are low....
See this is where integrated controls can take car of all of this for you... its sort of here no but not really! LOL

On the furnace control There is another AUTO | ON control along with the HEAT | OFF | COOL switch.

This is your thermostat. Again the manual fan is now triplicated possibly quadrupled if your air exchanger is tied to your furnace fan somehow! LOL Anyway you can set the fan to ON and the unit to cool and pic your desired temp. The fan on is recommended to keep air moving and reduce stacking of temps through out the house. There is a catch it maybe too noisy and cost extra...

A/C is real comfort vs cost issue... Choose your pain, hot and sweaty or larger bills

[Jake]

Thanks TKG. I found the install manual for the furnace 21B20H.

http://www.broan.ca/PDF/InstallGuides/300422852.pdf

The air exchanger (small cooler sized cube) does not seem to be wired to the furnace. That is the air exchanger kicks in at about 60% and the furnace does not.

I will try a few things and get back to you. The temperature stacking was obvious last week. I have tried my best to direct as much heat upstairs as possible but I am still figuring out the ducts in the basement.

[TKG26]

another thing thats possible is the air exchanger control has more adjustments then ur exchanger has. see this often.

[Monobloc]

-Run the fan 24/7 it helps eliminate the "stacking" effect you get where all levels of the home are at different temps. Continue mixing the air around between cycles helps keep an even temp

No, no, no! That works well during the wintertime, but terrible during the summertime. All that does is blow all the moisture off the A/C coil back into the house. Expect the humidity to go up another 20% by doing that. You want to run the fan on AUTO during the air conditioning season. My living room will shoot up to about 72% humidity by switching the fan to ON instead of AUTO.

Humidity is the absolute key to being comfortable at higher thermostat settings. Take a temperature reading at a supply vent and another reading at the return air grille. Should see a 20°F difference between the two. Bigger numbers are better. This is referred to as the delta temperature.

[TKG26]

WEll if your living in a 3 storey home(no basement) people get stacking effect. When your stat is satisified the house should close to desired humidity level.

IT works in the winter and can also be beneficial in the summer. Many of my customers have reported back to me suggesting that it was beneficial in adding comfort to there home....

STacking is not obvious in all homes but i have seen as much as 6-8 degree difference from the basement to the top floors. So keeping the fan rolling keeps these temperatures mixing. The basement offers a sourse of "free" cooling in that its naturally cooler. By keeping the air moving that air gets moved around the house... Humidity may go up a touch on the off cycle for a moment but that A-coil dries off pretty quickly after the condensor shuts down..

There is no right and wrong but i suggest experimenting with the continuos fan.

[I_Want_My_HDTV]

If there is that much "stacking" then something is wrong with the heating/cooling system design. Running the fan all the time drives up electricity costs, creates drafts that reduce comfort levels in Winter and adds extra heat that must be removed in Summer. All around, its a poor solution. I use an intermittent fan setting that runs the fan about 10%-30% of the time when there is no call for heat or A/C. Better thermostats have this option and, sometimes, it is programmable. Two and three story homes with serious stacking problems should have zone systems installed and other upgrades to increase efficiency, not have their efficiency reduced by running the fan 24/7.

[TKG26]

Some homes have the effect...the design is what it is. Like i said its not for everyone. The stacking effect is not obvious in all homes but some have it, the longer the system is not running(circulating) the more the differences can be felt.

Zoning is a nice option but a costly upgrade.. Most rather run the fan or lower the stat. I'm out there, people dont like to open there wallets to fix problems if there plans do not cover it.

With new DC fan motors on the market the hydo usuage is now minimal. about 60-80watts continuas versus 400-600watts. For the same reason people use portable fans to kool them selves, keeping the air in the home moving(with the furnace fan) in the summer offers some added comfort at a slight increase in hydro....

According to my TPI meter My temp rise in my furnace was 1.5F with everything off in the house today. One probe in the return one in the supply. A/C and heat have been off all day. I turned the fan on and my temp rise dropped to .3F within a few minutes. So there is not enough heat from the fan motor to heat the home but the mixing of the return air back to the furnace managed to give a near zero temp rise. And it managed to equilize that temp difference in the two plenums. My place is a split level home and the ductwork sucks(because of the style of home). The masterbedroom is above the garage and my kids room has poor air flow. We installed a duct boosting fan in both roomsand things are a bit better, but for the master when you have heat on 5 of 6 sides of your room its tuff at the best of times, we are comfortable though but there is a noticable difference from the basement to the bedrooms.


When the heat wave hits the A/C is running all day, so that short moment of off cycle wether or not the fan continues to run or not is not going to break the bank the condensor unit outdoors already did that!


Cooling requirments varies so much for people. I will go from an ICE box at 68F to a hot box at 80+F and both are happy! People either hate or love to use there A/C.

[wprager]

Checked the humidity today and it was 59%. Yikes! Of course with four kids runnng in and out of the house the doors sometimes get left open. I closed all doors/windows, ran all the bathroom fans and managed to get it down to 49% in fairly short order. Then evening came and it shot up again (baths/showers, I assume).

I'm going to try Monobloc's suggestion to run the fan on auto for a few days to see if it makes a difference. If it doesn't, I'm open for other suggestions.

[jwt873]

I like 21 - 22 degrees. (In the winter I keep my house at around 18 degrees and I'm comfortable).

I normally shut my AC off manually in the evening. Once the sun is down, the latent 'cold' in the walls and furniture usually keeps the house cool overnight... I turn the AC back on in the morning.

If you're running the AC when the temperature outside is under 20 degrees, the system can cool 'too well' and you could have ice forming on your evaporator coils. That will severely reduce efficiency.

[Monobloc]

I don't think you have to worry about too much ice forming at below 20°C. The A/C would run for such a short amount of time at below 20, that ice would be minimal.

[Monobloc]

Originally Posted by wprager

Checked the humidity today and it was 59%. Yikes! Of course with four kids runnng in and out of the house the doors sometimes get left open. I closed all doors/windows, ran all the bathroom fans and managed to get it down to 49% in fairly short order. Then evening came and it shot up again (baths/showers, I assume)

59%. Not too comfy is it? Doesn't matter how cold you set the thermostat. Even 49% is so so. I like to see 35-40%. Although 45% is alright.

Try running your A/C for 30 minutes on AUTO and then turn the thermostat up (system is completely off). Now turn the fan from AUTO to ON so you're just using the fan. Take a whiff near the vent. You'll smell a bunch of moist humid air blowing into the room. After about 20 minutes of fan only, the air will smell dry. But your house will be back at 59%.

Same thing happens in your car when you run MAX A/C for half an hour and then switch to VENT. You'll turn your car into a greenhouse with humid stuffy air. Probably fog up a few gauges if it's really humid outside.

[Phatboyc]

Some of you are running the AC lower late at night. Since your sleeping already this isn't for comfort. I understand it is easier for the AC to work at this time but is it really helping? The next morning your off to work. Doesn't the sun warms the house back fairly quickly the next morning negating any energy saved by lowering the temp at night?

[MarcP]

I would think the idea is to get to sleep and stay asleep comfortably. I doubt you'd be getting good sleep if heat and discomfort would wake you up at 2am.