Painful kitchen cooling dilemma

[ProperVenting]

Sounds like a lot of work, for what may turn out to be a fairly minimal gain

I like the mini split idea

The real challenge is to quantify that "fairly minimal gain" as it (new return) will work for all seasons. So how do we know in what savings it will result eventually for the whole year. Clearly, it's a difficult question to answer because it's more theoretical in nature and therefore intuitively we tend to resort to obvious "patch" solutions as I consider mini split as such. The real challenge is to find proper solution and compare them using some kind of science rather than gut. As far as I am concerned it is not the issue of money but rather what is RIGHT and what is WRONG

[LKJoel]

The real challenge is to quantify that "fairly minimal gain" as it (new return) will work for all seasons. So how do we know in what savings it will result eventually for the whole year. Clearly, it's a difficult question to answer because it's more theoretical in nature and therefore intuitively we tend to resort to obvious "patch" solutions as I consider mini split as such. The real challenge is to find proper solution and compare them using some kind of science rather than gut. As far as I am concerned it is not the issue of money but rather what is RIGHT and what is WRONG

I wouldn't view a mini split as a "patch solution". You have a room with an abnormal summer heat load, a mini split is the most effective and most efficient way to deal with it (aside from shading options)

Plus, in the winter time, you could run the fan only on the MS to mix the air in the kitchen, then run your furnace fan to mix the air in the house (depending on the installation of course)

You don't necessarily need a kitchen return to distribute the heat through the house, if you push air into a room, it has to come out somewhere..... How effective it will be, will be determined by the room configuration of course, but simple additions like a ceiling fan, or the fan on a mini split head used to mix the kitchen air, then using the existing duct work to spread it across the house may do a comparable if not better job

I like your thought process, but you may be over complicating things

[ProperVenting]

Plus, in the winter time, you could run the fan only on the MS to mix the air in the kitchen, then run your furnace fan to mix the air in the house (depending on the installation of course)

You don't necessarily need a kitchen return to distribute the heat through the house, if you push air into a room, it has to come out somewhere..... How effective it will be, will be determined by the room configuration of course, but simple additions like a ceiling fan, or the fan on a mini split head used to mix the kitchen air, then using the existing duct work to spread it across the house may do a comparable if not better job

Wow!! It never even occurred to me as I was totally focused on a MS as a cooling unit and not an axillary fan during winter time. I guess, the only question is how far I can push this air because the closest return is at the almost floor level and air has to travel quite a bit to reach it. Thanks for your kind words.

[S.T.Ranger]

I have a cooling dilemma that I was wondering if anyone here could offer some insights or suggestions for. My kitchen is a ruthless hotbox in the summer months due to its west-facing exposure and having plenty of glass (picture large floor-to-ceiling windows on the West wall and two Velux skylights on a 45 degrees slanted ceiling). Naturally, during sunny days in the winter it serves as a passive solar heat collector. So I am considering the following approach to deal with the heat load during summer time and capturing all generated solar heat during winter. I should also probably mention that I have pretty wide open floor layout, the existing cabinets are gutted, and I’ll have unrestricted access to the walls.
1. Currently in my 130-140 sq. ft kitchen there is no return line. Obviously code, architects and installers were more concerned

with cooking fumes than the unbearable summer heat. I remember reading somewhere that with every foot in height the temperature rises approximately 0.5 to 0.75 degrees, so in my case delta T between the floor and highest ceiling point can potentially reach up 10 degrees or even higher. Obviously there are several relatively simple and straight forward approaches to resolve those issues and I am listing the simple ones first:

a. Replace all glass on the wall with more efficient material; (very expensive and barely effective)
b. Replace Skylight regular glass with nanogel filled glass (new technology used by NASA to provide heat shield on spaceships); (very expensive and extremely effective)
c. Install blinds / shutters, either manual or solar controlled o existing skylights (I am not really sure about potential benefit).
d. Replacing hot halogen bulbs with much cooler LEDs should provide slight measurable relief.

2. Beyond the low-hanging fruit, let’s consider some more involved solutions:

a. Installation of inline 150-200 CFM exhaust fan (Soler or Fanteech) between the sloped ceiling rafters with exit @ the outside wall rather than roof (I do not want to deal with creating an opening in wooden shingle roof) with 2 purposes in mind.

i. Provide adequate cooking fumes exhaust outside throughout entire year.
ii. Provide some relief during hot summer by pulling hot air from under the ceiling and throwing it outside. I do painfully realize that this may have questionable benefits as outside hot air (granted a little bit cooler than the one collected from under the ceiling) will enter the house but assuming that A/C will be on at that time this air should mix with much cooler one so overall effect of installing inline fan maybe not at all w/o merits. This is just my gut and I can’t offer anything more of substance at this time.

b. Bring the return line to the basement to main return line and install intake grill as high as possible, however I also read somewhere that I need serious calculations in order just to extend that return as balance of return lines vs. supply will change. So, the question is do I have to bring another supply line to the kitchen (I can’t see how it will hurt) or should I close somewhere on the same floor return register? What would be the most sensible approach to address this issue?
c. I have currently 2 dedicated Carrier / Bryant 20 year old AC/heating systems, 1 per floor, with cooling capacity of 3 tons each. I am not planning to replace them with anything else right now as I am tinkering with idea of advanced and efficient geothermal installation.
d. Instead of messing around with the return line, how about installing an 11000 BTU dedicated mini split ductless A/C? This seems the least desirable approach but is definitely the most efficient one. I dislike this solution because maintenance is high and electricity costs are only on the rise.

TIA to everybody who can shed some light for me

I would suggest you add supply to the area. It is not that big of a kitchen so you could probably add another lead and this would be a more economical option. As far as wanting to use the collected heat in the winter I would ask if the Kitchen is cold in the winter and if this heat is needed. The additional supply would correct it if it is cold and if it isn't then it is a non-issue, really. A ceiling fan would be, I believe, a reasonable option, as it could be used for the purpose of dispersing cooking fumes as well as be useful on days when you do not need to run the A/C for cooling purposes.

You would need to examine the duct to see if this is possible, but usually taking another lead out of a trunk does not change the airflow in a significantly noticable way.

Hope that helps,

God bless.

[ProperVenting]

I would suggest you add supply to the area. It is not that big of a kitchen so you could probably add another lead and this would be a more economical option. As far as wanting to use the collected heat in the winter I would ask if the Kitchen is cold in the winter and if this heat is needed. The additional supply would correct it if it is cold and if it isn't then it is a non-issue, really. A ceiling fan would be, I believe, a reasonable option, as it could be used for the purpose of dispersing cooking fumes as well as be useful on days when you do not need to run the A/C for cooling purposes.

You would need to examine the duct to see if this is possible, but usually taking another lead out of a trunk does not change the airflow in a significantly noticable way.

Hope that helps,

God bless.

Thanks for the vote of confidence but so far we are in overwhelming minority

[ProperVenting]

Ok, I gave in and after careful consideration I decided to install in my kitchen cheap Soleus KFTHP09 mini split and at the same time bring return line. Originally, I was planning to install 1100-1200 CFM sidewall exhaust fan but putting in cheap mini split seems like a better option.

[ProperVenting]

Ok, I gave in and after careful consideration I decided to install in my kitchen cheap Soleus KFTHP09 mini split and at the same time bring return line. Originally, I was planning to install 1100-1200 CFM sidewall exhaust fan but putting in cheap mini split seems like a better option.

I guess the idea of installing cheap Soleus MS is out of the window, somebody suggested Mitsubishi and it appears to be great choice

[LKJoel]

Please keep me posted as to the effectiveness of installing the RA in the kitchen.

Do you notice kitchen smells in other rooms of the house?

Was it as effective as you expected for providing heat to the rest of the house?

I only ask because situations like this do come up from time to time. Any experimenting I have done in my own houses have all proven to be ineffective, and would not have been worth the money, had the labour not been free. If you achieved favourable results, I would love to hear about them, pictures, temps etc.

Good luck with the install, I think you will enjoy the mini-split, both in terms of comfort and energy consumption

[ProperVenting]

Please keep me posted as to the effectiveness of installing the RA in the kitchen.

Do you notice kitchen smells in other rooms of the house?

I can't say for sure because, first of all I have pretty much open floor layout and secondly very ineffective current downdraft vent despite its well known name. It has the blower inside kitchen cabinet and it is loud and totally worthless as the pop-up is only 7.5". Bad design, really bad.

Was it as effective as you expected for providing heat to the rest of the house?

I am hoping it will be effective for several reasons:

1. I will be replacing current "garbage" downdraft vent with pop-up hood close to 15" high and external blower mounted on a sidewall.This will hopefully resolve all issues with smell and noise.
2. I am still contemplating installing additional sidewall exhaust fan up to 800-1100 CFM to deal with summer heat build up under my sloped kitchen ceiling. Should you ask "why bother", the answer is, I would like to check myself how effective that solution could be on its own merits.
3. Regardless of this additional fan I am planning, I will be installing small Mitsubishi MS air conditioning only (9K-11K).
4. My dilemma now is, whether I need an ERV for make up air and I don't know the answer to this question yet because I'm not quite sure how much air I will be pulling out of my kitchen @ any given time. Obviously the worst case scenario is close to 1400-1700 CFM if both vent and exhaust fans are engaged. But remember I do have totally open floor plan which should relly mitigate the necessity for make-up air somewhat.

I only ask because situations like this do come up from time to time. Any experimenting I have done in my own houses have all proven to be ineffective, and would not have been worth the money, had the labour not been free. If you achieved favourable results, I would love to hear about them, pictures, temps etc.

Good luck with the install, I think you will enjoy the mini-split, both in terms of comfort and energy consumption

Thanks for your continious and strong support, I am planning to start the project in 30-40 days, still in process of buying required equipment and supplies. I will keep u posted privately if u don't mind, - there are only few people here with whom I would like to share my victories and/or fiascos / disasters.

[energy star]

I can't say for sure because, first of all I have pretty much open floor layout and secondly very ineffective current downdraft vent despite its well known name. It has the blower inside kitchen cabinet and it is loud and totally worthless as the pop-up is only 7.5". Bad design, really bad.
(Look at the duct under the house, youn have too many 90's, too long of a run or a bad install.)


I am hoping it will be effective for several reasons:

1. I will be replacing current "garbage" downdraft vent (Installed correctly? Did YOU look at the installation) with pop-up hood close to 15" high and external blower mounted on a sidewall.This will hopefully resolve all issues with smell and noise.
2. I am still contemplating installing additional sidewall exhaust fan up to 800-1100 CFM to deal with summer heat build up under my sloped kitchen ceiling. Should you ask "why bother", the answer is, I would like to check myself how effective that solution could be on its own merits. (thats massive neg air)
3. Regardless of this additional fan I am planning, I will be installing small Mitsubishi MS air conditioning only (9K-11K).
4. My dilemma now is, whether I need an ERV for make up air (No) and I don't know the answer to this question yet because I'm not quite sure how much air I will be pulling out of my kitchen @ any given time. Obviously the worst case scenario is close to 1400-1700 CFM if both vent and exhaust fans are engaged. But remember I do have totally open floor plan which should relly mitigate the necessity for make-up air somewhat.



Thanks for your continious and strong support, I am planning to start the project in 30-40 days, still in process of buying required equipment and supplies. I will keep u posted privately if u don't mind, - there are only few people here with whom I would like to share my victories and/or fiascos / disasters.

Your kitchen area is only 130-140 sq ft? You want to add a mini split, exhaust fan & ERV? How many sq ft of glass are we talking about? If you look at the the money to install all this equipment, the the money you will spend running them all, you could have bought new glass to knock down that radiant heat gain in the first place. Your plan is still a patch, you seem to be blind by it's complexity, cost and design to justify the money it will take to install.

If you had a two zone system conditioning the home now, one system for upstairs bedrooms and one for the downstairs living area. During the day you are not in the bedrooms, this is when the kitchen is hot. Take a supply duct from that system and installing the kitchen. This will work fine all day long. Then at night, when the heat gain is non existent in the kitchen the motorized damper will close directing the air back to the bedroom where it's needed.

You are doing a lot of work for a very small kitchen.

[LKJoel]

FYI open concept floor plan will in no way mitigate the need for make up air. If you exhaust 1700 CFM of air, you WILL get 1700 CFM of outdoor air entering the home, no floor plan can reduce this.

In the summer time, you are far better off dealing with the extra heat with the mini split than with an exhaust fan, see my logic below

Ex1 you cool the air with MS. The kitchen air may be really hot, but the moisture content is very low, so total heat content is very low. At 18 SEER the MS will make short work of the extra heat.

Ex 2 you exhaust the hot air outside. You remove 1700 CFM of conditioned air, and bring in 1700 CFM of hot AND humid outdoor air (very high overall heat content), the house AC then has to work overtime at 13 SEER to remove all the extra heat AND all the extra moisture.

By the way, I don't remember your location, I'm assuming you get high humidity in the summer time. If you live in a dry summer climate, the difference would not be as drastic

Like I said, I anxiously wait the results of your experiment, I just want to make sure you are properly educated first, and give several scenarios a fair test

IMO 1700 CFM is a TON of air to be exhausting! That may hurt on the utility bill

[ProperVenting]

FYI open concept floor plan will in no way mitigate the need for make up air.

I remember reading about that effect somewhere but I could be wrong.

If you exhaust 1700 CFM of air, you WILL get 1700 CFM of outdoor air entering the home, no floor plan can reduce this.

That is the worst case scenario and I may have overshot quite a bit. I would say that on average it wil be less than 700-900 CFM

Ex 2 you exhaust the hot air outside. You remove 1700 CFM of conditioned air, and bring in 1700 CFM of hot AND humid outdoor air (very high overall heat content), the house AC then has to work overtime at 13 SEER to remove all the extra heat AND all the extra moisture.

See my previous response above

By the way, I don't remember your location, I'm assuming you get high humidity in the summer time. If you live in a dry summer climate, the difference would not be as drastic

It is Midwest and it is extrwmely humid!!

Like I said, I anxiously wait the results of your experiment, I just want to make sure you are properly educated first, and give several scenarios a fair test

That is the objective

IMO 1700 CFM is a TON of air to be exhausting! That may hurt on the utility bill

See my prior responses

[ProperVenting]

IMO 1700 CFM is a TON of air to be exhausting! That may hurt on the utility bill

There was another reason for additional more powerful sidewall exhaust fan under the kitchen ceiling, I was hoping that it will deal not only with build up heat during summer but also will get rid off remaining cooking odors which were not eliminated by pop-up downdraft vent.