Nick T - 6A (MN)
I have two walls of a bedroom that are adjacent to my garage attic. I am hoping to beef up the insulation on the outside of the wall in the…
I have a home that was built this year - mostly just code standard for air tightness and insulation in Minnesota. The question i have is that we have a…
Interesting article - didn't Interesting article - didn't realize this tech was already to market in the US. Hopefully for early adopters here in North America the 'new' technology kinks have been worked out already in Europe. The natural gas prices are quite high ($1.50/therm), surprising, thought the prices nationally didn't vary all that much. Also are notice your summer/winter gas drying costs are nearly identical, are you seeing that high of gas prices even in the summer?
Posted: 09:21 am on January 30th 2013
I have had a differential pressure gauge on my home filter for my past two homes and in both cases it seems like anything more then a Merv6 or 7 and the amount of pressure drop (restriction of flow) really shoots up. Quickly gets past typicall 'design' filter pressure drop... which is typically Merv3 or so (if taken into account at all....) In each step up in Merv rating that it is the equivalent of a very dirty filter. So a very grey dirty Merv6 filter had the same airflow restriction as a clean Merv7. I am able to get low cost TrueBlue Merv6 or 6 at Menards in my area. I tested the Merv-less Filtrete and even their lowest rated one had a higher pressure drop then a 7 (by a good amount) IIRC. If you don't have a pressure meter or gauge - make sure you carefully watch furnace temperatures (return and discharge) to ensure proper flow is being maintained (make sure not to high of a difference, don't want past the specifications). Also once you put in a high eff filter it will change the dynamics of the system, and effect your flow vs design. Might need to change motor lead to a faster speed to overcome additional pressure drop... Would be possible to test multiple filters if you had an amprobe to put on fan motor.... adjusting fan lead to maintain a constant differential air temperature (or airflow sensor or static pressure). That would give you a cost for that flow restriction. Would be a good bit of tinkering... Often an additional return can be added to the other side of the furnace - which will help increase total surface area of filtration. This will reduce the velocity of air across the filters and reduce pressure/flow loss.
Posted: 09:18 am on February 5th 2013
Depending on the amount of time you are home, how much cooking you do on the stove, how many times people shower (or go #2) with the exhaust fan on or off, all effect your need for ventilation. However, one thing to note regarding ventilation requirements for a small house - is that in a 2700sqft home each time the exhaust fan runs for 20minutes or each time you open the door it maybe isn't that much fresh air as a % of total home air volume. However when you have a 700sqft house , each of those occurrences (which happen every day at regular intervals) are quite a bit more significant(4x in fact ). Timely 'flushing' (open windows or run exhaust) of your home (warm front in winter on a sunny day, cool front in summer, open windows most of the spring/fall) will also help negate energy losses.
Posted: 09:31 am on February 5th 2013
Home Depot (and menards i think) carries OSI SC-170 and 175 in larger tubes - and it appears to be a comparable 'black goo' sealant for the same use. I have used it in my home and offgasing wasnt' alarming in any fashion. Builder used a comparable white version - still 'thick peanut butter gooey' 2+yrs later.
Posted: 03:04 pm on February 9th 2013
Another thing he might be refering to is maybe the below ground 'gutter' using foamboard? Article on GBA refers to it as "Inground Gutter" but for water containment using poly i believe. So in-lieu of insulating the foundation wall you could insulate horizontally a foot or two down to keep subsoil/foundation warmer.... ?
Posted: 11:20 am on February 19th 2013
Another element to consider in this case (an already installed system) is the controls. The input/output needs at this point won't help you.... If the thermostat is set to allow for 5 CPH ! (cycles per hour) which is a common default (since many hvac people don't change thermostat settings based on install). Set this for heating and cooling to a very low number to help with cycling (and increased dehumidfiying in summer). Recommend a setting of 1 or 2. Although if temperatures dictate usually it will still cycle a bit more than the setting itself. Some thermostats allow changing a deadband (allowable decrease in temperature before furnace turns on). Could be set very aggressive (.25-.1°)causing it to turn on/off to maintain a tight temperature. It might be also placed in a location that is getting influenced by furnace airflow/registers. Causing it to turn off thinking it is at setpoint, however shortly after airflow has stopped it believes it is back below setpoint. Could also try to direct more of your heating flow to the exterior of your home, further from the thermostat to reduce the spikes in temperature. Also having a lower then design internal temperature (65 vs 72°) could also be reducing run times possibly by reducing your heat loss.
Posted: 11:14 am on February 26th 2013
I can see the payback of being more of a comfort and durability issue return- if the exterior door is near living space (not part of a mudroom or large entry way area). If near living room it could provide an easy source for cold drafts, cold interior surface temperature both of which will create comfort issues (even at decent thermostat temperature setpoints) Also with a majority of the day in the winter being dark...and cold.... a cheaper door will have issues with frosting, condensation....this frequent freeze/thaw cycles can further weaken seals and window over time. Probably a minor issue... (especially at the cost savings.... you can replace it if it somehow failed)
Posted: 11:21 am on February 26th 2013
I have a pressure gauge across my filter at home, it most definitely changes with dust accumulation. I don't have the actual numbers off the top of my head - but its on the scale of say.... clean cheap pleated filter is .3"wc differential and noticeably dirty is .4"wc... I change it every 1-2 months during heating or cooling seasons since they are <2$. My guess is the person was measuring the power consumption on a non-variable speed fan (old style, non-ECM) - expecting energy to go up when dirty (as people often state...).
Posted: 01:23 pm on November 13th 2013
To get an idea of makeup potential in the home you can add up your total square footage of windows, multiplied by the leakage specification from the manufacturer. In many cases the leakage will do a decent job of equalizing pressure/airflow. Add to that door leakage ratings... Also each of your exhaust fans, water heater, etc (when off) will also provide small amount of makeup air leakage in most cases.
Posted: 01:49 pm on November 13th 2013
Yeah, no doubt about there being more leakage. In many out of sight locations. However doors/windows seem to be the easiest to quantify being that there is a specification on it. Which over the many windows/doors in a home the average spec should be close enough for makeup air calcs. As kind of a minimum check, instead of using 'assumed leakage' by sqft + year built (per MN code for instance, which gives higher values) Personally when I turn on the dryer or couple exhaust fans, I feel better knowing that the makeup air is being pulled in through windows/doors... then being pulling into wall cavities :-/ However, i'm only kidding myself, since stack effect forces, wind, and generally leakiness of my nice code built house, likely isn't effect much when i turn on my fans. :(
Posted: 12:44 pm on November 16th 2013