Check the outside of the housing for buildup of debris, which can impact the efficiency of the unit. Grass clippings and dryer lint particularly can foul the grates. Be careful not to dent the heat exchanger fins, if exposed (more common on older units). These look alot like a car radiator, or the outside of a window A/C unit. Keep the area around the unit free of plants and materials, to help the air to flow freely for best efficiency.
There is absolutely no mention of insurance on the website. I even read the customer documents and saw nothing about it. This doesn't mean there is no insurance option. I just did not get to go through with the reservation process, so it's entirely possible you can purchase insurance with Door to Door. But most competitors at least offer some information about insurance - at the very least whether it's available - on the website, so it does not bode well.
We offer the high-performance, ANSI/NSF tested and California certified CB Tech Water Filters Water Filters, the top-rated water filter by Consumer Reports. These quality filter systems are Made in the USA and ANSI/NSF tested and certified for Standards 42 & 53 to remove Chlorine, Chloramine, VOC's, PCBs, Lindane, Silvex, MTBE Chloroform, 2,4-D, Lead and other heavy metals, Giardia, Cryptosporidium and Pesticides, Fertilizers, Xylenes and many more unpronounceable organic compounds. Some models of CB Tech water filters will also even filter out Arsenic. And for the most difficult water treatment situations, we also offer Reverse Osmosis Systems that remove the broadest spectrum of contaminants. And don't forget NSF Standard 177 Certified Shower Filters, available in both hand held and shower head shower filters by Sprite and Rainshow'r.