Portable Ac with heat single hose for winter heating ?

[ecomodded]

Its natural for me to watch the numbers like a hawk.
Have 3 years of graphs on hand to draw from to upload with daily power consumption vs the average outside temperature to compare to this upcoming years numbers.
The kill a watt meter numbers are priceless they show elapsed time vs power consumption.

Have been and will be keeping the house at 21 to 22c so can enjoy some savings in the form of heat , enough of 18 and 19c. I have grown weary of it.
Its been 20 days with the portable but the heating season does not really begin until November.

So far the consumption about the same as its always been about $57 bucks in electricity a month with utilities about $33 of that is for heat

The unit was cycling on and off every 10 minutes after the duct was added so I put it on a timer at 1hr off 1/2 hour on cycle for a 33% run time. Tonight will be a test its been good with that setting for the last 4 hours or so.

In closing we have a few nights with 2 an 1*c night time temps coming up I will be sure to watch it Kwh consumption closely and will post its day time Kwh usage vs night time results / numbers.

I will be sure to log them and post the numbers maybe with a few charts for accuracy .

[ecomodded]

To start with here is next weeks weather



This is what the AC is dealing with atm

This is the *houses* daily KWH vs outside average temp since the machine has been hooked up



Thought its a good time to show the power consumption before the added duct and new on/off schedule change the numbers






Elapsed time since the AC was hooked up followed by the KWH consumption , atm its 3 kwh off a 50% run time cycle over the last 20 days.

[DEnd]

Originally Posted by ecomodded

Im using the AC in dual hose mode now and its been running with night temps between 3 and 8c regularly. Its been on the kill watt meter for 505 hours , its working out to run 50% of the time 50% off for a average of 500w an hour.

That costs me $35 a month

I want to use $70 to $75 on heat and $25 to $30 on utilities for $100 total electric costs not $100 on heat as I typed earlier.

So I can double the current heat out put Im using now to heat with a average outside temp of 10c the winter lows are usually 0 to -1 or 2c


Be nice if it squeezes heat out of the air still when its below zero

Im hoping it does as that's the time it can reduce electrical consumption the most

It'll pull heat out of the air as long as there is heat in the house. The question is will it cause you to run your furnace more or not. Where that point is, is entirely dependent on how much stack effect driven air leakage your house has.

As long as you are only de-powering the stack effect you shouldn't see an increase in gas usage, even in below freezing temperatures.

Think of it like this, when it is cold outside the stack effect drives a certain amount of ventilation in the home. Heated air inside the home rises creating a higher air pressure at the ceiling than at the floor. This is because we are adding energy to the air. This is also the reverse of natural air pressures. outside the air has a higher pressure at the ground than it does 20' up (generally anyway). This creates some fairly major pressure differentials that drives air flow through the building.

We can use mechanical fans and change how the pressures are inside the house. By negatively pressurizing the house with mechanical ventilation we are in effect doing the same thing the stack effect does, only we are controlling where the air exits from. With your unit as long as the CFM is less than or equal to what the stack effect would be, then it actually acts like a HRV that is probably around 90+% efficient. *that has nothing to do with energy use only the amount of "available" energy the unit is able to harvest from the ventilation air. Of course to do that we need to be cognizant of how we are adding the heat back into the house and where we are pulling air from, it is possible that we could just end up pulling more air through the house and not doing anything about the stack effect.

[ecomodded]

Hey Dend I was not thinking about the stack effect but can see how this plays a role. Mixing the air temperatures differences via a return duct or equivalent would help to elevate the pressure differences.

I gave up the hope of heating with the single hose set up , its negative pressure was MUCH stronger then I was lead to believe by the online quoted numbers.

I was reading the portable ac would exhaust 1/3 its front sides output our the rear that was wrong it turned out it expels 240 CFM out both the vents. making for much too strong negative pressure to allow heat to warm the upstairs.

I tried it out on two days it did nothing but super heat the downstairs room room to 35c

The intake hoses in the photo are strung out the window the unit breaths 100% outside air now. It no longer creates negative pressure.

Its basically acts as a non inverter mini split at this point with me controlling its on / off cycles via a timer.

to be clear this unit uses two fans one for the front heat and one for the exhaust so the two air streams never meet.

[ecomodded]

Temp went down to and is currently at 1c with viability at 75 feet due to Fog.

The house was at 17c this morning the ac air temp at the top of the stairs was 84*f

I want to wake up to a warm house so this will not do

The ac was moved to a 1hr on/off cycle yesterday this was not enough time for the unit to heat the house during the cold foggy night so i switched it to run solid for the next 4 hours to warm the house up.

Im not liking the timer before the unit maintained the temperature and would run more or less according to conditions. I put it on the timer as it was short cycling with about 3 on/off cycles a hour after the vent/duct was was added. Before the duct it was running on a long 1 hour on/off cycle at top heat.
To overcome this poor thermostat control using the timer will take it off the timer and let it run and short cycle as it wants too.
Had good luck using its built in thermostat before the duct was added it maintained the upstairs temp very well.

All in the ac did all right given the conditions and low run time hours last night , I hope it does better without the timer in the same conditions

[jeff5may]

Short cycling these smaller units doesn't really hurt your energy efficiency. They don't take long at all to ramp up, and the jolt to get started doesn't consume a considerable amount of power. However, the unit I had ran both fans the moment the compressor started. In either mode, if the condenser side fan was delayed a few seconds, the unit would ramp up faster and consume a little less energy.

Unless the unit is overrated for the space, most heat pump systems don't deal with temperature setback very well. Completely opposite of gas heaters and furnaces. Then again, it's actually difficult to find a permanent gas furnace rated less than 50kbtu. I replaced my "right sized" gas furnace in the trailer (14x70 champion steel box) with one from a double wide because it cost so much to run in frigid weather. The overrated furnace paid for itself the first winter.

[ecomodded]

The short cycling has been warm cycles each cycle gets that pre warmed compressor and condenser heat.
What bothers me is those last 4 or 5 degrees come on slower closer to the end of a 10 / 15 minute on cycle.

The short cycling issue has been fixed

Cause was it uses a internal thermostat to control its on/off cycles that was being cooled too quickly by the exhaust fan



Was leaving the fan on 24-7 this caused the vent to draw cool air over the ac's thermostat cooling it.

Before the ac duct the exhaust fan cycled the rooms air 24-7 without issue it helped to maintain a even temp between floors.

The fix was this Inkird 308 temp controller which arrived yesterday


One plug controls a heating circuit the other cooling

It allows me to turn off the fan after the AC shuts down , prevented it from cooling the AC's internal thermostat.

The temp probe is placed in free air above the Fan box where some of the AC's warm air hits it.

Can fine tune the start up delay by changing the relays cooling setting.

At a 75*setting the fan stays off for 15 minutes , at a 77* setting turning the fan off quicker it leaves the AC thermostat warmer allowing it to cycle on a 40 to 60 minute cycle.

It worked out well with last nights test the house was 19c this morning without short cycling.

[AirSepTech]

Been a looong time since a login/comment, I look time to time, got the heads up this am on email,,,this thread I have been through myself.

Single hose no good, too much infiltration. I even tried exhaust into the basement, maybe pick back up some heat in daytime. Nope. Just lowered the temp too much, pushed cold back to 1st floor. Returned them, 2 Haier 12k units, approx. $350ea.

Got a new 14kbtu two-hose at HD bargain bin,,,$150-no hoses/manual/box.

It is IN my basement, intake/exhaust out the window, heat ducted to the first floor thru a floor register. Some balance of pressure/flow between. Works good down to 25f, about 85-90f outlet temp. Backed with portable resistance oil heaters($10 at Walmart closeout). All on timers.

This worked as primary heat 2010-2012, 66-68f, small heaters in bath, bedroom on a timer, down comforter/elec.blanky haha. Natural convection worked like a dream, 2nd floor.

This setup ran 30-35kwh/day average, some 50kwh days. Under $100mo mostly. $.07kw/h.

Northern Nevada, 6k feet asl, sub-zero ALOT. When propane was@ $3/gal, bill was $150-300mo, when the whole family was there. 30kbtu cast iron Vermont D/V stove. 900sf all 3 floors, base/1st/2nd. Basement stays 50-55f until it goes sub 0 for days.

I did use the stove some, maybe 10 times/2-4hrs a winter.

I was home maybe 10hrs 6days a week, back then I had a good pay/crappy lifestyle job. :lol: 2 homes/long distance marriage.

By comparison (call it what you will), my home in Idaho ran $100/mo on nat. gas. But back then my wife was running the thermostat...so ??


Don't know if this helps, but you are not alone! I was trying to save $$, running 2 homes/heating.

I rolled R19 on top of R30 in the attic, sealed stuff, a lot done. It was a heat gain/loss effort to learn/improve. Actual heat loss was 10-15k btu/h at night, average. What I found was a lot of mis-info, plenty of 'tribal knowledge' out there in the world of heating.

I should post the solar air/air window heater@160f outlet, some other fun stuff

Good Luck!

[ecomodded]

Thanks AirSepTech and it is good to hear of your heating outcome using the dual hose.

25*f / -3.9 c is a low temp for these portables to be making heat , will be set if this model performs the same.

These newer Ac's are designed different then the older portables

A few years back

First single hoses they used a fan that split its air between the front heat and rear exhaust port wasting cooled or warmed air via the exhaust duct.

Next they made a dual hose with 3 fans

it used one front fan one exhaust fan and one slightly smaller intake fan. this arrangement lowered air infiltration down but due to the differences in fan cfm it still made some negative pressure.

this was done to insure a air exchange took place for good air quality I read.

Then the dual hose came out with one front fan and one exhaust fan used to intake with as well as exhaust , eliminating any negative pressure.


For the best Mod use a single hose ac with dual fans not a triple or single , with heater.

These portable ac heaters seem to have a good defrost system

[ecomodded]

Was a cold night last night its noon and still @ 1*c

Woke up to warm house at 19.8c the AC moved from a 50% run cycle up 20% to a 70% on duration.



This upcoming week is a chilly one Winter has arrived early by the looks of it.

temp at the top of the stairs 30 feet down the duct has been in the high 80's low 90's. The downstairs room is at 61* this lowers the heat gain I see upstairs , if the downstairs was at 70 degrees I would be reading the upstairs vent in the high 90's.

The temp at the AC"s vent taken with a IR gauge is 115*f at 240 CFM = 13,9996.8 BTU using the temp difference vs air flow method , with a 54* difference.

The Air temp is 61 downstairs at the condensers intake and 115 at its outlet.

The vent normally sits between 115 and 125*f with 135* found if I point the IR temp gauge deep into the vent. The 115* is taken from the top outside of the vent a few inches away from the opening.

I used to take the Vents temp off the vent door but it was removed to fit the Duct.

The door removed with a slight pry with a screw driver to dislodge one of the press fit hinges from there it slipped off without issue.