I also own the ash vac thats pictured here, it has been a good investment. I figured if I was spending almost $4000 on my insert, and I needed premium pellets for maxium heat and performance then I also needed the right tool to clean up the ashes. Granted the ash vac is expensive, but if you look at how it's built you know its going to keep working for you for many years. The filters (there are 2 ) dont have to be changed, you simply take the unit outside and remove them, and shake them off then put them back on. I find this to be an advantage over having to change paper filters in the shop vac all the time. A shop vac will do the job, but most will leave you with a micro fine ash particle in the air, and most times you wont see it, but you will be breathing it in, the ash vac cuts down on this tremendously.
The ash vac has a unique " shaker" rod, you simply unscrew a brass plug, grab the metal rod and sort of wiggle it and shake it up and down, this motion knocks off any ash dust from the filter and suction returns to normal. I think its a great idea, theres no need to remove the lid and tap on the filters or brush them off as you would have to do with a regular shop vac. The 5 gallon steel tank also holds a lot of ash, I only emptied mine twice last year, and I burned 4 tons.
These ash vacs are expensive, and many people cant see spending that kind of money on them, but you know something, you invested a great deal of money on your pellet stove, or insert, and you insist on getting a good quality pellet to burn, so why not spend a little more and get the right tool to compliment your stove with? The only thing I use the ash vac for is ashes, its a dedicated appliance, and it gets the job done nicely, and safely.
Remember Safety should be your main concern when youre working with any kind of heating appliance, such as pellet or wood stoves, ash vac's are safe, they are designed for ashes, shop vacs are not.
The dealer installer I bought my insert from told me he wouldnt even consider using a shop vac for cleaning the stove with, he's had an ash vac for over 5 years and he does all the units in his showroom with it, and its still running like new. I bought my ash vac from totalvac.com it was on sale and they added the 10 year warranty when purchased from them.
If you do get an ash vac, after you vacuum your ashes up for safety reasons, let the ash vac sit for a while before you put it into a closet or store it away. Not that its going to go up in flames, but having a fireman for a neighbor I have learned a lot about fire safety, and its just good practice to let these ash vacs sit for a little while just to make sure nothing inside it is going to smolder or smoke. The hose on the ash vac's are fireproof, the vac itself is a steel tank, the filters are flame proof, so its a fairly safe appliance, one that will give you peace of mind when you do put it away.
I highly recommend the all steel ash vac over the $20 Home Depot vaccum, Ive used both, the Home Depot vac now resides in a land fill, RIP little buddy you just were not designed to suck hot ashes.