Or buy free-standing child playard units (they're a little expensive bought new, but I bought them pretty cheap used) and just put a little "fence" around the space heater (and anything else you want to keep the pets out of). These are the units we have. I bought 4-6 panels for about $20 at kids consignment sales.
http://www.walmart.com/ip/North-States-Superyard-Xt-Gate/8457890?ci_src=14110944&ci_sku=8457890&sourceid=1500000000000003260330
http://www.ebay.com/itm/Superyard-Colorplay-Playard-/130811141418?pt=LH_DefaultDomain_0&hash=item1e74f39d2a

I have a Vornado space heater. It does not get hot on the outside and is fairly low to the ground. I highly recommend it -- definitely not a concern around pets (or preschoolers, for that matter).

We want to put a space heater in our kitchen. We obviously would only use it when we are in the room, but from time to time we'd step out of the room for a few minutes, turn our backs to attend to the stove, etc. I don't think our dog would knock over a space heater on purpose, but I definitely think he'd be curious and sniff it and accidentally hit it with his fluffy wagging tail. He is a 45 lb goldendoodle. Is any space heater safe around pets? If so can you recommend yours?