The main issues we encountered with using the BIS Ultra to heat the house are:
- Difficulty in constantly attending to the fireplace to keep it optimally stoked.
- Poor ash-handling system.
- Frequent glass cleaning.
- Dry air.
Because the firebox only holds a practical maximum of 1.5 cubic feet of wood, the fuel must constantly be replenished if the maximum output of the fireplace is required. This is difficult to achieve as someone must constantly be monitoring the fireplace day and night. If you wait too long, more kindling must be added to the coals so as to relight the fire. This can be quite time-consuming.
After burning steady for 2-3 days, a significant amount of ash builds up in the fireplace. Although it could be possible to sweep most of the ash into the ash pan and keep some coals in the fireplace, it is simpler to let the fire burn out and clean it completely out so as to start fresh. This allows the still-hot ash and coals to be removed from the house in a single metal bucket
The other reason for doing a complete clean-out after 2-3 days of burning is to clean the ceramic glass in the doors. After 2-3 days, in spite of Security Chimneys' touted "air wash system", the glass tends to blacken with creosote build-up, especially if the wood used isn't completely dry. The normal air flow in the fireplace tends to cause the outside edges of the door to be particularly black because most of air wash comes across the centre of the doors. Also, there is smoke produced when the the fire is restarted (like first thing in the morning) and smoke condenses on the glass due to the air currents in the fireplace. Although many people just use to newspaper to clean the glass, we found that it was also necessary to use a Potassium Hydroxide (KOH) ceramic glass cleaning solution to get the glass clean. This is not a fun job once you've done it several times.
Although the primary combustion air for the BIS Ultra comes from outside, the secondary air for burning the smoke (introduced at the tubes in the top of fireplace) is drawn from inside the house. Although we have a modern house (built to the R-2000 standard) that includes a Heat Recovery Ventilator (HRV) with humidistat control, the air is dry during the winter because the significant amount of secondary combustion air.
After several years of use, there is now some spalling in the refractory so continued continuous use will require replacement in a few more years.