Are heat lamps essential for keeping newborn puppies warm? I always thought if the room temperature was kept above 75-80ºF, day and night, they would not be needed.

Any advice please.

No, they're not essential by any means. If you're rearing a litter in an outside kennel or barn, then yes, they would be needed. But it's easy enough to make a room in a house quite cosy enough.

I find the best thing is to have either a roofed-in whelping box, or put the box under a table, and put a blanket over the whole thing to make an enclosed den within a room. The bitch's warmth keeps that very snug - in fact sometimes you need to lift one side of the blanket to let the heat out!
:)

I agree with JG but I do like to use one in the summer when I don't want the heating on generally and during the night when I like to turn the heating off.  A local spot of heat also allows the bitch to move away for a cool down if she likes, although they don't tend to do this in the first few days so it is important to use a min/max thermometer to check you are not overheating her.
The last litter I had was born in a heat wave and rather than use a heater I was using fans to cool the room during the day!

When I had a summer litter I had a plug in radiator next to the whelping bed in the kitchen.  Only drawback is it makes the bitch very hot, but at least it can be turned on and off as required.  I also use heat pads which can be warmed in a microwave, I wrap them in a pillow case and put under the vet bed.
Lorna

No you dont need them for an indoor litter in summer as long as the room is 75-80F and draught free, in fact thats probably preferable as too much overhead heat can distress the mum.

My last litter born indoors in mid winter: We put up a heat lamp but the mum would not lie with the pups as she was too hot. Luckily the room is quite a small one to keep cosy, 10x10, my "office" so I used an oil filled radiator with a thermostat which was great . The room stayed the right temp, mum laid happily with the pups and all was well AND I was toasty cosy next to them while on the pc. :-)

I would also check with your Dams breeder!

I recently had a litter and thankfuly the Dams breeder advised me right the way through. She told me that they were not to have a heat lamp/heat pad. Oh how cruel thought i but she knows best.
We relied then upon the radiator in the room.
By day 2 one of the puppies started constant whingeing and i thought we were going to lose him. Rushed him down the vets as he was dehydrated. Turns out even the radiator was too much for this particular breed.

So off went the heating, and even had to have the top window open!!

I certainly wouldnt advise this for any other breed, just my own experience. (This breed when born in Finland, the pups are born, have their first feed and as soon as they are dry they go outside! Now just think how cold it is there!!!)