A homeowner in Burgess, VA wanted to improve the insulation in their attic. They had been experiencing rooms that were too hot in the summer or too cold in the winter and they could never seem to make the space comfortable. They had high energy bills and wanted to know what options they had for not only making their home more comfortable but reducing their heating and cooling costs.
Their attic was being used as a storage space, and the homeowner did not want to lose the ability to put items here. Currently, the attic had fiberglass insulation on the flat, and on the different elevations in the space. Fiberglass insulation is most effective when it is enclosed on all sides and in an airtight attic. With gaps in the ceiling assembly, the fiberglass is essentially acting as a filter for the air flowing out of the home. The attic, which is hotter than the outside temperature, heats up the ceiling in the summer. This heat radiates down into the rooms below, heating them up and making it difficult to cool down. In the winter, the ceiling is cooled down by the attic which is about the same temperature as it is outside. Rising heated air meets the ceiling, gives up its heat, and falls in a process called convective looping. This leaves rooms feeling cold and drafty and harder to warm up.
The attic had several recessed lights, which allow about 10 (cubic feet per minute) CFM of air leakage, which is about 10 basketballs of air escaping per minute and the lights cannot be touched by insulation. At construction holes are drilled from the conditioned space to the unconditioned attic for wire and utility lines, these spaces also allow for significant air loss. Top plates, where walls meet the ceiling, are also a considerable source of air loss in a home. All these gaps allow for conditioned air to flood into the attic and new, outside air is pulled in at the bottom of the home via the stack effect. This is a huge contributor to the high energy bills the homeowners are experiencing.
To address these concerns, and help keep the homeowner’s storage space, together we determined to air seal and insulate the attic. First, we installed Rockwool can light covers over all the recessed lights and sealed them to the ceiling. The Rockwool covers are fire retardant, can be covered by insulation, and prevent air from flooding out around the lights. We then air sealed around utility penetrations, closing those holes created at construction. The steps taken for air sealing will reduce the loss of conditioned air from the rooms below into the attic space. This allows the conditioned air to stay in the house longer and less outside air to be pulled in at the bottom of the home.
We then installed a dam around the catwalk and pull down stairs to prevent insulation from falling in. Baffles are then installed to prevent insulation from impeding the ventilation of the attic. Lastly, we blew in a fresh blanket of cellulose insulation. The cellulose product used is 85% recycled material and 15% new material. It also contains a borate solution that deters pests. Cellulose is made of very fine pieces that nest together creating less air space than fiberglass. This means it allows less air to pass through it and has a higher R-value per inch. This reduces the heat transfer to the ceiling from the attic space, therefore reducing the heat radiating to the rooms below in the summer, and the heat lost in the winter.
This solution has left the homeowners with even temperatures throughout their home. They no longer have to close off rooms that are too uncomfortable to use and can take advantage of every room in their home. They are also seeing lower energy bills and less wear on the heating and cooling unit. All without losing the storage space in their attic.