Renovation & Design
Renovation & Design
Improved air quality will tame fetid odours
Question: I am hoping you can help me with a quick question. My son and his friends are around 20 years old and like to hang out at our home, in our basement. The basement is finished, but nothing fancy. I find the basement has an odour, I guess a smell of boys that age, when everyone leaves. Can I use my HRV for the basement in order to remove these odours? Or, do you have any other solutions?
Thanks, Brian.
Answer: Odour control is not one of the primary functions of a heat recovery ventilator (HRV), but it could be an extra benefit, if installed and used accordingly. It would require additional ducting and control installation in your basement, but should be worth the cost and effort, even if it only improves airflow and moisture control in that area.
Odour elimination, especially in a basement, is often not a simple matter. Because that level of our home is typically cooler than the upper floor, condensation on cooler surfaces is much more likely. Also, because the cooler air will settle in the lowest areas in your home, it will take extra effort for the heating, and cooling (HVAC) systems to collect and recirculate that air throughout the home. That can lead to damp, musty odours, and in worse situations to mould growth. Regardless of the effectiveness of my following suggestions for your specific youthful smells, improving air circulation in the finished basement will definitely be beneficial.
I can certainly sympathize with you about the unique odours that often emanate from teenage and young adult males. As a former boy’s hockey coach, I regularly had to leave the dressing room when all the teenage players would arrive and take out their equipment, prior to a game or practice. The offensive smells were not because they forgot to hang out their gear after the last skate, and were barely noticeable when the same kids were younger. When they became teenagers, it was completely different.
I am not sure if the stinky athletes were simply a product of hormone production as they reached puberty, or a combination of that and other factors. Use of colognes and scented soap and shampoo products may have been a contributor, or a change in personal hygiene. In your case, the boys are above the legal age for drinking, so some of the offensive smell may be caused by beer, or legal cannabis, consumption. If they are leaving unwashed food and drink containers in the area, it will only add to the pungency. So, the first suggestion for mitigating the problem is to make sure they clean up after themselves, especially rinsing out used beer cans or bottles, before they are taken back for deposit returns and recycled.
All the blame should not be directly attributed to the young guys, who are simply enjoying a very fun part of life. Part of the issue may be poor air circulation in your finished basement. Too often, homeowners, and some contractors, forget to install sufficient heating ducts and registers in the basement upon building a rec-room. The most common mistake is to forget the return air registers, completely, when building the walls. It is easy enough to cut a few warm air ducts and install ceiling-mounted registers nearby, but return air installation is more complex. Since the return air ducts for the rest of the house are normally located in between the main floor joists, that puts them at ceiling height for the basement. Since the heated air entering the basement from the furnace ducts will settle to the basement floor as it cools, locating any return air registers will require some pre-emptive planning and installation. Return air ducts will have to be installed inside the basement partition walls to allow installation of registers near the floor. If the registers are not located in that area, they may collect the heated air from the ceiling registers before it properly circulates and cools, preventing proper heat distribution. Because cold air moves more slowly than warm air, larger or additional numbers of return air registers may be required. So, ensuring that you have an adequate return air system in the basement will be priority number one and will be critical for proper HRV setup.
Adding registers and ducts for the basement for use by your HRV is a good idea, which will help with overall air movement and moisture management. Unlike the HVAC system, the HRV will only require one set of those in each room, for intake of air to the ventilation unit. Since the HRV already has ducting connected to the return air plenum near the furnace, the presence of return air registers in each room, as recommended above, will suffice. If those are not installed, the HRV will not effectively collect the damp, cool basement air before the furnace replaces it with dryer heated air. That additional air movement should lower the humidity in the basement, preventing condensation and directing some of the odours outside through the HRV exhaust. You will also need to install a timed control switch, just like in the bathrooms and other areas where the HRV registers currently exist, to turn on the unit when the odourous boys are present, or after they have departed.
Adding proper controls, ducts, and registers for your HRV in your finished basement should help prevented unwanted odours, but also improve the overall comfort level of the HVAC system, as well. By improving the air quality through circulation and drying out the air in the basement, a properly set-up HRV intake is worth installing.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)(cahpi.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
Renovation & Design
Electric water heater likely better choice than gas
Question: I changed over from a gas water heater to electric some years ago. It was done at the time that I replaced my gas furnace with a high efficiency unit. The advantages at that time were as outlined in your previous article. Since then, is there not an option to eliminate the chimney and vent the gas water heater in the same manner as the gas furnace is vented?
Robert H.
Answer: Replacing an older natural gas water heater with an electric unit makes the most sense, when upgrading to a high-efficiency furnace. It is the quickest and most cost-effective, in the short term, as well as most environmentally friendly. For those reasons, direct vent high-e water heaters are rarely seen in our area.
I frequently recommend an upgrade to a water heater powered by electricity, to my clients, when upgrading an older furnace. This is also discussed when the client is a potential buyer of a home which has a furnace over 15 years old. The typical life expectancy of the furnace, at 20 – 25 years, is often double that of its water heater counterpart.
If the furnace is really old it may be naturally aspirated with a vent hood connected directly to a metal flue. Very often, the older gas-fired water heater shares this flue by way of a separate, but connected, pipe above the water heater vent hood. That connection is one of the main reasons to switch to electricity for the power supply for a replacement tank. Because all new natural gas furnaces are direct-vent, high-e models, they will no longer need to use the old chimney for venting out the combustion products.
Switching to electricity for water heating, along with running a high-e furnace, will allow discontinued use of the old chimney. This will have the minor benefit of preventing natural heat loss through the old flue when the appliances are not in use, which may increase your heating costs. When the old flue is no longer required, it can be capped and air sealed at the top and bottom and remain unused.
To directly address your question, there are another couple of alternatives to a standard electric water heater, which will allow the same discontinuance of the older vent. You could replace your older naturally aspirated gas water heater with a high-e model, or a gas-fired on demand water heater. Those units do vent out directly through a PVC pipe, like the newer furnace, but have several issues which make them less desirable. Firstly, the additional vent pipe will have to be directed outside your basement. That will require drilling an additional hole or holes in your foundation or exterior wall. It will also require more ceiling space in the basement and area outside, where it exhausts. That will add some cost to installation, but may be similar to the cost for the circuit breaker and wiring installation for an electric model.
The main reason for ruling out the high-e or on demand water heaters is initial cost. Both those water heater units are considerably more expensive than either a standard gas-fired model or an electric tank. That additional cost may be recouped over time by the lower operating cost of natural gas vs electricity, but it will take several years for that to even out.
The final reason to install an electric water heater vs. natural gas is the environmental one. As we strive to reduce the carbon footprint of our homes in the future, to reduce harmful emissions that lead to climate change, eliminating any source of those pollutants is desirable.
Installing a direct-vent high efficiency water heater to replace an older one is possible, but not as practical as an electric unit. Electric water heaters are much less costly, easier to install, longer lasting, and emissions-free, which all adds up to a better overall choice for your home.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)(cahpi.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
Renovation & Design
Adding rigid insulation to new home will enhance comfort, efficiency
Question: We are building a new home, with the exterior finish being stucco. We are toying with the idea of installing some type of solid insulation over the sheeting, to reduce heat loss through the wood studs. Is this possible, necessary with the new homes of today, and is it cost effective? Are there other options?
Thanks for your time and attention.
Hank H.
Answer: Insulating a new home on the outside of the exterior wall sheathing is becoming more common and is certainly possible with today’s technology. The key is to properly plan for the insulation in that location, to prevent issues with proper window, door, and foundation installations.
There is no reason that rigid insulation on the exterior of the walls cannot be incorporated into the construction of a new home. In fact, there are research studies that suggest this is the preferred location for air and moisture-resistant insulation. Installing it on the outside of the wall cavity will do exactly what you suggest, prevent heat loss from the home through the wall studs. Because there may be almost continuous contact between the interior drywall and the exterior siding in many homes, there can be an effect known as “thermal bridging” occurring. This is heat loss associated with direct transfer through building materials, like the wall studs or rafters. This can be observed, in older homes in particular, by using a thermal image camera, or by observing snowmelt patterns on roofs. In those situations, heat will be lost directly through the rigid building materials, even if they are well insulated between the studs. The studs, sheathing, and some types of siding will conduct heat much better than any type of insulation sandwiched between.
There are two main ways to prevent heat loss through thermal bridging. The first is to put a continuous layer of high-density insulation on the interior of the wall studs, prior to installation of the drywall. This insulation will prevent the heated air in the home from contacting the inside surface of the wall studs, which will effectively stop any thermal bridging from occurring, except through metal fasteners, which may be used to hold the insulation in place. It may be achieved with rigid extruded polystyrene sheets, high density polyurethane spray-on foam, or other forms of rigid foam sheathing. Unfortunately, insulating in that manner has a downside.
Insulation with foam sheathing on the interior of a wall will achieve the desired effect of preventing heat loss and warm air leakage into the wall cavity, but will leave that cavity quite cold. If the insulation within the cavity is not extremely well sealed, especially at penetrations like electrical boxes, some warm air will leak in. Because that cavity is substantially cooler than the air from the heated living space, condensation is likely to occur. That can lead to mould growth, rot in the wall studs, and general moisture damage. All of those things are items we hope to prevent when insulating a modern home.
If we change our thinking and install a good layer of thermal protection on the outside of the wall cavity, we significantly minimize the chances of moisture related issues. With the insulation on the outside of the wall we will prevent heat loss to the exterior of the home, but will not substantially cool the wall cavity. Even if there is additional batt insulation between the studs, we will still have some thermal bridging occurring, but it will stop at the interior surface of the outside rigid insulation. That may actually become a benefit rather a detraction, as it may help warm the wall cavity. Having a warmer wall, except at the exterior insulation, will prevent condensation of any warm air that leaks in from the home. That will minimize the chances of any moisture issues from air leakage and negate the need to air seal inside the studs to the same degree as traditional insulation methods.
The main issue with installation of rigid foam insulation on the outside is the added thickness of the insulation, itself. To achieve minimal air movement through that insulation layer it will normally have to be a minimum of seven to 10 centimeters thick. That will make the exterior walls substantially thicker, which will have to be taken into account in the design. The main issue will be with the placement of the windows and doors, with requirements for wider sills, jamb extensions, and flashings. Most manufacturers will have these standard products made for a typical two by six wall assembly, but not for thicker ones. So, you will have to take this into consideration when locating the windows and drawing up the plans. Brick moulding may have to be extended to reach past the exterior insulation and siding, and/or extensions of the jambs on the interior, to allow proper installation of window casings. Finally, the location of the walls on top of the foundation walls, or floor structure, may have to be altered to accommodate the extra thickness of the entire exterior wall assembly.
Adding a layer of exterior rigid insulation may be a superior way to insulate a modern new home, which can help prevent condensation inside the wall cavities. This will have to be taken into consideration when creating the building plans, by the designer and the builder, to have all the other components adapted for the extra thick walls.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)(cahpi.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com