My folks built a tight house back in the 80's and experienced nothing but problems since. Largely due to the high humidity levels due to limited air exchange. In the summer when humidity outside is high, they relied on 24-7 use of their air conditioner, solely to dry out the incoming air, plus often a dehumidifier. Unfortunately, the house often still felt "stale". In the wintertime, despite exterior humidity plummeting, they still experienced 60% inside the house (summertime was upwards of 70%). Thanks to the recent introduction (and improvements to) HRV systems, my parents installed one this year. It ran continuously for 3 months (January - March) and cost them about $300 to run during that time. Now, keep in mind that there was 30 years of moisture in that house... Their house now sits below 40% humidity (they don't like it below 30 for their comfort), has regular fresh airflow and they expect their heating costs to be LESS next winter since the removal of the dampness in the air actually makes a cooler room feel warmer. I also installed an HRV, and it's wonderful. In my brand new construction, 1 month of continuous running brought my humidity under 40% and provides plenty of fresh air intake. I didn't see nearly the increase in costs. My place always feels fresh. The cost of the unit was around $1000, and it has a programmable "thermostat" that can be set to a variable or continuous operation. The actual install we did ourselves, which was surprisingly easy. Not even 4 hours start to finish, with just one hole cut in the rim joists. After seeing what my parents experienced for the last 30, $1000 and 4 hours seems like a pretty easy way to ensure future home comfort.

thanks for the honeywell link sniffdog I'm kinda late for the discusstion, but wanted to contribute. I'm all about the build tight ventilate right. But..unless you actually test for tightness of building envelope the question is if you will need fresh air or not. Lots of homes are not tight enough to require fresh air. And contrary to the install on the link provided by sniffdog..I wouldn't run my fresh air supply along the roof line. Too hot in my climate. The temp of the air in august would be too high for most central systems to dehumidify and cool. For the program I work with any home with less than .35 air changes per hour requires mechanical ventilation. There is even a ventilation standard..ASHRAE 62.2 to determine how much (how many CFM cubic feet per minute) of air is to be added to the home. But first you have to test the house with a blower door to determine if the .35 ach has been met. If in fact the house is tight enough to require fresh air. then you want to carefully choose your location that the fresh air will be drawn from. clean it..measure it and condition it before it enters the living space of the home. I usually install a 12x12" filter back grill under a porch this allows you to filter the air, and the location is where air is cooler, as opposed to attic. an insulated sealed duct to the return side of the central system is added, this runs along the floor of the attic. At the return air plenum a barometric damper is installed, set to cfm as determined by number of occupants and ashrae 62.2 the damper opens for instance when stove vent is in use and both bath fans are in use. as the fans turn off..the damper closes. These fans are to vent the humidity out of the living space. less humidity allows for RH levels to even out for better iaq and a healthy house. When the house is not calling for air ( fresh air required to keep house from going into a negative pressure) the damper remains closed. by putting the fresh air to the return side of the system, it is dehumidified before entering the house. the idea is to keep the house under a slight positive pressure so that it is not sucking through unsealed holes. This is just the way that has evolved for me over the years to address this situation. Keep in mind that these homes were tested and amount of fresh air...and need for this added air..was verified and not just based on home owner or builder assuming that the structure was actually tight enough to require fresh air. skuttle 216 is one example of a barometric damper. install the set up described above..set the weight on the damper..and forget about it..except for changing the filter in the 12x12 fbg. keep in mind that mine is a hot humid climate best of luck.

In general, a typical mounting height for range hoods is 20 to 24 inches above the cooktop for electric stoves and 24 to 30 inches for gas stoves. Note that these are general averages and it is crucial that you look-up your range hood installation manual. Depending on certain vent hoods, 30" is what is required, but that's usually for gas stoves. Since yours is electric, they put off less heat than a gas stove, so your lower height is prob ok. (although, for comfort while using, I'd want it higher) . instead of guessing, why not look at the specs for your particular vent, and your stove, and see what they recommend? Code requirements diff from city to city, and also need to adhere to a few other acronyms. this should settle that argument (as for the backsplash, do whatever you like as mentioned above) What Is Required, and What Isn't? If you don't live in California, you may not even be required to have an exhaust system in the kitchen (be sure to check), but if you install one, the U.S. Department of Energy (DOE) requires it to conform to standards established by the American National Standards Institute (ANSI) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The relevant standard, which forms the basis for the California ventilation code, is ASHRAE Standard 62.2-2007. California requires kitchen ventilation in all new construction and remodels, and even if your local authorities don't require it, you should address it anyway. You can satisfy most local codes by installing a range hood. The capacity of range hoods is measured in cubic feet per minute (cfm), and you determine the required capacity by calculating the total heat output of the range in British thermal units (Btu) and dividing by 100 (for intermittent systems) or by 400 (for continuous systems). A range hood servicing a 40,000 Btu gas burner stove, which is standard, should have a capacity of 400 cfm if it's the kind you can turn off and on. If it stays on continuously, it only needs to be able to transfer 100 cfm, or a quarter of the capability of an intermittent system with an on/off switch. An electric stove doesn't generate as much heat as a gas stove, and it emits no combustion gases, so the capacity of the range hood is generally less, and you'll be compliant if you follow the requirements for gas burners. What Should the Exhaust System Do? The DOE cites ANSI/ASHRAE/IES Standard 90.1-2010 as the determinant for energy efficiency when it comes to range hoods. It lists two requirements that apply to all kitchens. The first is that they must use a limited amount of makeup air, which is air drawn from other rooms in the house, to avoid wasting energy expended by heating and cooling this air. The second is that they must not be short-circuit hoods, which are those that draw makeup air from outside. They should draw all the makeup air from inside the building with no outdoor air allowed. You can select from a number of options when choosing a range hood, including cabinet undermount systems, wall mounts (which include wall-mount exhaust fans) and downdraft systems that circulate air downward instead of upward (which is often necessary to vent a stovetop on a kitchen island). All of these should have a fan capable of at least five air exchanges per hour, which means they exchange all the air in the room at least five times every hour while running. Many ducted systems have a duct hidden inside a cabinet above the vent hood. Requirements for a Makeup Air System When you run an exhaust fan in the kitchen, it draws air from other parts of the house, and if your house is well sealed and energy efficient, you could encounter these problems: Negative pressure could draw cold air from outside through the chimney and heating vents, and your heating bill could go up. The exhaust system doesn't get the air it needs and operates at a lower efficiency. Running a kitchen vent fan without makeup air can create negative pressure that pulls exhaust gases from water heaters or other gas-burning appliances into the house, an effect called backdrafting. Because modern homes are better insulated and more energy efficient than they used to be, the IRC was revised in 2009 to require that systems that exhaust more than 400 cfm require a system to provide makeup air at the same rate. The revision was further modified in 2018 to state that the makeup system must be capable of preventing depressurization in the house greater than three pascals. Some builders try to satisfy this requirement by creating holes in the wall, but this obviously reduces the energy efficiency of the house and drives up the heating bill. The code-approved method is to provide a fan that blows conditioned air into the kitchen whenever the exhaust fan is on. This fan is usually synched with the exhaust fan so that they come on and go off at the same time. Many building authorities regard this section of the IRC as more advisory than compulsory, and builders don't always follow it. Installing a makeup air system can add 3 to 10 percent to the cost of a kitchen renovation, which also provides negative incentive for homeowners to comply. However, failure to do so could mean significant extra energy costs, and it could shorten the life of the exhaust system, so the extra expenditure is probably worth it. Getting the Most From Your Range Hood One of the most common mistakes homeowners make when installing a range hood is to put it too far above the cooking surface. When you do this, the suction from the fan isn't strong enough to attract all the cooking gases and microscopic particles, and they are free to circulate throughout the kitchen. However, you don't want the hood to be too low, or it will get in the way, so 24 inches above the cooking surface is the recommended distance. Vent hoods should be close to 24 inches above the cooking surface. Many stoves come with their own hoods, and the hood is usually the right size for the stove. If you're installing a standalone hood, it's easy to make it too small, and that makes it less efficient. In particular, many people choose a hood that isn't deep enough to cover the front of the stove in order to avoid bumping their heads on it, and such a hood won't capture the gases from the front burners. Be generous when sizing the hood to make sure it will do the job it's supposed to do. Another mistake you might make is to choose an exhaust fan that's too small for your needs. Even if you have a small stove with a total output of only 10,000 Btu, you should choose a hood with a minimum capacity of 200 cfm to be sure all the air from the stove will circulate. Like recirculating hoods, ducted hoods also come with filters, and if you want to make sure your hood is working to its maximum efficiency, you should clean or replace this filter frequently. Personally I'd want it higher so it wasn't in my face while cooking.

"Thank you, Kaseki! I’ve been reading your past posts-would you mind sharing again what cooking device/range hood/ makeup air system you chose and why?" You may find images of elements of my kitchen in various posts. I won't repeat them here. Also, some hood flow parameters may be found in FAQ I. Please note that my kitchen reno planning began in 2007, with most purchases of appliances made at the end of that year. Delivery was taken significantly later for most items, but well in time to confirm measurements and interface details. Explaining rationale would make this tediously long, take too much of my time, and jack this thread. I owe a kitchen photo to the FAQ II thread, and one or more should appear in the fullness of time. The cooktop: I have two induction cooktops, a 36-inch Frigidaire Gallery (replacing a 36-inch Electrolux clone Kenmore that failed after 5 years or so) and a Cooktek 3500W induction wok. These are set in soapstone over cabinets in which there is added stone support and wire racks for pans, providing maximum air volume for cooling. The hood system: Overspreading these is Wolf's largest Pro Island hood set at 34.5 inches above the counter. The hood connects to a damper, then a Fantech silencer, and then a Wolf (Broan) 1500 CFM roof blower (which has a damper). (As I have explained many times, once installed in a hood system blowers cannot flow their rated CFM due to pressure losses. I have measured, however, about 1000 CFM with presently passive MUA and no other household exhaust blowers operating.) Duct is 10-inch. The secondary hood system: There is a secondary system comprising a pair of ceiling registers (14 x 20 if I recall), 3M Filtrite filters in the register boxes, a damper, silencer, and roof mounted NuTone down-blast blower. I believe this blower is rated 600 CFM, but can't find my literature for it as it was originally bought to provide additional flow for a '70s cooking center with miniscule blower performance. The registers are ceiling mounted over a pair of Wolf wall ovens. The MUA: I have planned an active MUA system, but all parts have not yet been acquired. There seems to be no end to new "required" projects. The system as it presently exists is operated passive, and comprises a highly ventilated attic with an additional roof-mounted down-blast commercial blower housing for eventual ducted air intake, a one-inch pleat 24 x 24 furnace filter (to be replaced with a lower pressure loss 4-inch pleated canister version, a 30 x 30 heat exchanger connected to my oil-fired hydronic heating system, and a 36 x 36 diffuser at the end of a hall that connects to the kitchen. The control system for this is intended to keep the kitchen pressure equal to the outdoor pressure (which will be the attic pressure once the MUA is ducted). Some elements of this are place. A Fuji computer module in a DIN control array next to my furnace will attempt to adjust its natural frequencies (poles and zeros) such as to make a stable MUA system independent of the main hood flow rate, the wall oven vent flow rate, and bathroom blower flow rates. The differential pressure sensor upstream and motor downstream control loops are 20 mA current type. Separate sensors and controls are used to keep the heat exchanger from freezing when not in use and otherwise keeping the air passing it temperate. Blower will be the largest that can get into the attic that Fantech sells that incorporates the 10 Vdc control voltage motor. (I forget the part number.) This wasn't available back ca. 2010, nor did Fantech list a motor controller that could handle that size motor back then. If starting from scratch, I would investigate the present offerings of Electro and Fantech to minimize my work, but large flow rate in an assembled unit would likely not fit into the attic without removing the diffuser and heat exchanger for a one-time installation. While balanced air pressure is highly desirable for several reasons repeated often on this forum, I should note that my System 2000 oil furnace has its own MUA and a sealed exhaust stack installed within the original brick chimney that served the previous one- and two-generations-back Beckett boilers. The hot water storage is heated via a hydronic loop on the furnace, and the dryer is electric. Hence, back-drafting of combustion appliances is not an issue. To deal with the flow to the MUA heat exchanger (capable of 120k BTUh if necessary) as well as the longer reaches of my house hydronic plumbing, I use a larger (higher head vs. flow rate) Taco pump than is usual.