I wrote up the pattern for one of the hot water bottle cozies I made.
I even made a pdf...
Look in the extended entry for the pattern
The Coziest Hot Water Bottle Cover Ever
I designed these as gifts for my husband's sisters and parents. Part way through knitting the third one I started to think, "Is this a weird present? Hot water bottles and cozies all around!" But by then it was too late to turn back and everyone loved them. In fact, I got the flu the weekend I gave these gifts and ended up using one of these for the weekend. The cozied hot water bottle just might become your new best friend. These bulky, fuzzy babies keep the water warm for hours and hours and hours.
yarn
One large skein super bulky wool (one skein is enough)
One skein angora
needles
size 10 USA or whatever you need to get gauge
gauge
9.5 sts = 10 cm
(.95 sts/cm)
instructions
combine one thread wool and one thread angora
FRONT
Cast on 12 sts
row 1: P2, K8, P2
row 2: P1, inc 1, K1, P8, K1, inc 1, P1
row 3: K1, P2, K2, put 3sts on a cable needle and hold to the front, K3, K3 from cable needle, K1, P2
row 4: K1, inc 1, K2, P8, K2, inc 1, K1
row 5: K2, P2, K8, K2, P2
row 6: P1, inc 1, P1, K2, P8, K2, inc 1, P1
row 7: K3, P2, put 3 sts on a cable needle and hold to the back, K3, K3 from cable needle, P2, K3
Repeat rows 8-15 four times total--rows 8-39
row 8: P3, K2, P8, K2, P3
row 9: K3, P2, K8, P2, K3
row 10: P3,K2, P8, K2, P3
row 11: K3, P2, K2, put 3 sts on a cable needle and hold to front, K3, K3 from cable needle, P2, K3
row 12: P3,K2, P8, K2, P3
row 13: K3, P2, K8, P2, K3
row 14: P3, K2, P8, K2, P3
row 15: K3, P2, move 3 sts to cable needle and hold to back, K3, K3 from cable needle, P2, K3
row 40: P1, dec 1, P1, K2, P8, K2, dec 1, P1
row 41: K2, P2, K8, P2, K2
row 42: P1, dec 1, K2, P8, K2, dec 1, P1
row 43: K1, P2, K2, move 3 sts to cable needle, K3, K3 from cable needle, P2, K1
row 44: K1, dec 1, K1, P8, K1, dec 1, K1
row 45: P2, K8, P2
bind off
BACK
Cast on 12 sts
row 1: K12
row 2: P1, inc 1, P10, inc 1, P1
row 3: K14
row 4:P1, inc 1, P12, inc 1, P1
row 5: K16
row 6: P1, inc 1, P14, inc 1, P1
row 7: K18
row 8-39 Knit on the knit side, purl on the purl side.
row 40: P1, dec 1, P14, dec 1, P1
row 41: K16
row 42: P1, dec 1, K12, dec 1, P1
row 43: K14
row 44: P1, dec 1, P10, dec 1, P1
row 45: K 12
bind off
FINISHING
Block both pieces
Sew the front and back together along the sides
Turn RS out
Pick up 20 or 24 sts around the top with dpns
Rib K2, P2 around for neck until desired length
Use a piece of scrap yarn to attach the plug to the the hot water bottle
Insert the bottle into the cozy
Using this Pattern as a Recipe for Designing Your Own
You can really use this pattern as a recipe for designing your own Hot water bottle cozy. First, choose whatever yarn you want and whichever size needles. Next, figure out your guage: knit a 10 cm swatch and figure out your gauge by measuring how many stitches it takes to get 10 cm and divide by 10. That number will be your stitches per inch (your gauge).
A standard hot water bottle measures 19 cm at its widest and 12 cm at the top and bottom. Multiply the gauge number you just got by 12 to see how many stitches you have to cast on and by 19 to see how many stitches you need to increase up to. Take some graph paper and draw out your pattern.
Once you have your shape laid out on a graph paper you can pick whatever cable you want to run up the center.
When you measure to see how close you are to the top of the hot water bottle, be sure to pull the material to the right width. Stretch it horizontally across the bottle, or you will end up with a cover that is too short.
When you get to the height where the hot water bottle starts to narrow again, decrease until you have 12 cm again. At this point you will want to knit the back and then sew them together before knitting the ribbed neck of the cozy with double-pointed needles.
You don't need any kind of closure at the bottom. Just slip the hot water bottle in and it will stay fine.
